Document and Entity Information - USD ($) $ in Billions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Jan. 31, 2018 |
Jun. 30, 2017 |
|
| Document Information [Line Items] | |||
| Document Type | 10-K | ||
| Amendment Flag | false | ||
| Document Period End Date | Dec. 31, 2017 | ||
| Document Fiscal Year Focus | 2017 | ||
| Document Fiscal Period Focus | FY | ||
| Trading Symbol | ED | ||
| Entity Registrant Name | CONSOLIDATED EDISON INC | ||
| Entity Central Index Key | 0001047862 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity Well-known Seasoned Issuer | Yes | ||
| Entity Current Reporting Status | Yes | ||
| Entity Voluntary Filers | No | ||
| Entity Filer Category | Large Accelerated Filer | ||
| Entity Common Stock, Shares Outstanding | 310,397,070 | ||
| Entity Public Float | $ 24.7 | ||
| CECONY | |||
| Document Information [Line Items] | |||
| Entity Registrant Name | CONSOLIDATED EDISON CO OF NEW YORK INC | ||
| Entity Central Index Key | 0000023632 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity Well-known Seasoned Issuer | Yes | ||
| Entity Current Reporting Status | Yes | ||
| Entity Voluntary Filers | No | ||
| Entity Filer Category | Non-accelerated Filer |
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- Definition If the value is true, then the document is an amendment to previously-filed/accepted document. No definition available.
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- Definition End date of current fiscal year in the format --MM-DD. No definition available.
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- Definition This is focus fiscal period of the document report. For a first quarter 2006 quarterly report, which may also provide financial information from prior periods, the first fiscal quarter should be given as the fiscal period focus. Values: FY, Q1, Q2, Q3, Q4, H1, H2, M9, T1, T2, T3, M8, CY. No definition available.
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- Definition This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD. No definition available.
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- Definition The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word "Other". No definition available.
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- Definition A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument. No definition available.
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- Definition Indicate "Yes" or "No" whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure. No definition available.
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| X | ||||||||||
- Definition Indicate whether the registrant is one of the following: (1) Large Accelerated Filer, (2) Accelerated Filer, (3) Non-accelerated Filer, (4) Smaller Reporting Company (Non-accelerated) or (5) Smaller Reporting Accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure. No definition available.
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- Definition State aggregate market value of voting and non-voting common equity held by non-affiliates computed by reference to price at which the common equity was last sold, or average bid and asked price of such common equity, as of the last business day of registrant's most recently completed second fiscal quarter. The public float should be reported on the cover page of the registrants form 10K. No definition available.
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- Definition The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Indicate "Yes" or "No" if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. No definition available.
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- Definition Indicate "Yes" or "No" if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Is used on Form Type: 10-K, 10-Q, 8-K, 20-F, 6-K, 10-K/A, 10-Q/A, 20-F/A, 6-K/A, N-CSR, N-Q, N-1A. No definition available.
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- Definition Trading symbol of an instrument as listed on an exchange. No definition available.
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- Details
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- Definition Income before interest income, interest expense and income taxes No definition available.
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- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Cost of oil and gas purchased during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Cost of electricity purchased as well as fuel used to generate electricity used in operations and sold during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The aggregate revenue, whether regulated or unregulated, derived from the generation, transmission and distribution of electricity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Revenue derived from the regulated (by a federal, state, or local government or agency) generation, transmission and distribution of [natural] gas. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Interest and debt related expenses associated with nonoperating financing activities of the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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| X | ||||||||||
- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of interest expense classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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| X | ||||||||||
- Definition Amount of revenue and income classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of expense related to nonoperating activities, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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| X | ||||||||||
- Definition Amount, after sales adjustments, returns, allowances, and discounts, of revenue classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Total increase in earnings in the period representing the cost of equity (based on assumed rate of return) and/or borrowed funds (based on interest rate) used to finance construction of regulated assets, which is expected to be recovered through rate adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Revenue generated from providing steam products and services to various industries. Steam is used in oil refineries, pulp and paper mills, chemical production (such as ethylene and ammonia), food and grain processing, and textiles. Steam is also used in the heating and cooling of urban commercial and residential buildings. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition All taxes not related to income of the entity or excise or sales taxes levied on the revenue of the entity that are not reported elsewhere. These taxes could include production, real estate, personal property, and pump tax. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of other operating expense of regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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Consolidated Statement of Comprehensive Income - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| NET INCOME | $ 1,525 | $ 1,245 | $ 1,193 |
| OTHER COMPREHENSIVE INCOME, NET OF TAXES | |||
| Pension and other postretirement benefit plan liability adjustments, net of taxes | 1 | 7 | 11 |
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 7 | 11 |
| COMPREHENSIVE INCOME | 1,526 | 1,252 | 1,204 |
| CECONY | |||
| NET INCOME | 1,104 | 1,056 | 1,084 |
| OTHER COMPREHENSIVE INCOME, NET OF TAXES | |||
| Pension and other postretirement benefit plan liability adjustments, net of taxes | 1 | 2 | 2 |
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 2 | 2 |
| COMPREHENSIVE INCOME | $ 1,105 | $ 1,058 | $ 1,086 |
| X | ||||||||||
- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount, after tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition Increase decrease in current portion of intercompany tax payable. No definition available.
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- Definition Increase (Decrease) in System Benefit Charge Liability No definition available.
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- Definition The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition For the entity and the disposal group, cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits are not generally reported as cash and cash equivalents. No definition available.
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- Definition Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Cash Flows between a transferor and a transferee attributable to newly transferred assets related to either a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Future cash outflow to pay for construction in progress expenditures that have occurred. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The increase (decrease) during the reporting period in the aggregate amount of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The increase (decrease) during the reporting period in the value of expenditures made during the current reporting period for benefits that will be received over a period of years. Deferred charges differ from prepaid expenses in that they usually extend over a long period of time and may or may not be regularly recurring costs of operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Change during the period in carrying value for all deferred liabilities due within one year or operating cycle. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in current receivables (due within one year or one operating cycle) to be collected from an entity that is controlling, under the control of, or within the same control group as the reporting entity by means of direct or indirect ownership. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) in obligations owed to an entity that is controlling, under the control of, or within the same control group as the reporting entity by means of direct or indirect ownership. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in income taxes receivable, which represents the amount due from tax authorities for refunds of overpayments or recoveries of income taxes paid. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the aggregate value of all inventory held by the reporting entity, associated with underlying transactions that are classified as operating activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of increase (decrease) in operating liabilities classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of increase (decrease) in receivables classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of increase (decrease) in obligation for pension and other postretirement benefits. Includes, but is not limited to, defined benefit and defined contribution plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the amount of outstanding money paid in advance for goods or services that bring economic benefits for future periods. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the period in the amount of cash payments due to taxing authorities for non-income-related taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash inflow or outflow for the increase (decrease) associated with funds that are not available for withdrawal or use (such as funds held in escrow) and are associated with underlying transactions that are classified as investing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash paid for interest. Includes, but is not limited to, payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Increase (decrease) in cash associated with the entity's discontinued operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The amount of debt that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Other increase (decrease) not attributable to current expense nor cash payments during an accounting period in estimated obligations recorded for probable future costs attributable to environmental contamination issues. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of income (expense) included in net income that results in no cash inflow (outflow), classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The cash outflow from construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash (inflow) outflow from investing activities classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The net cash inflow or outflow from the costs of disposing of plant, whether by demolishing, dismantling, abandoning, sale, and so forth during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash outflow in the form of ordinary dividends provided by the non-wholly owned subsidiary to noncontrolling interests. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Cash outflow in the form of ordinary dividends to common shareholders, preferred shareholders and noncontrolling interests, generally out of earnings. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow from the amount invested for projects in hopes of getting a future return or interest from it. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of payment for pension and other postretirement benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash inflow from parent as a source of financing that is recorded as additional paid in capital. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash inflow from the additional capital contribution to the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash inflow from issuance of shares under share-based compensation arrangement. Issuance includes, but is not limited to, exercise of stock options and similar instruments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The net cash inflow or outflow for borrowing having initial term of repayment within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash inflow from the sale of property, plant and equipment (capital expenditures), software, and other intangible assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Definition Current portion of intercompany tax payable No definition available.
|
| X | ||||||||||
- Definition Represents the noncurrent portion of deferred tax liabilities and the reserve for accumulated deferred investment tax credits as of the balance sheet date, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. A noncurrent taxable temporary difference is a difference between the tax basis and the carrying amount of a noncurrent asset or liability in the financial statements prepared in accordance with generally accepted accounting principles. In a classified statement of financial position, an enterprise shall separate deferred tax liabilities and assets into a current amount and a noncurrent amount. Deferred tax liabilities and assets shall be classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, shall be classified according to the expected reversal date of the temporary difference. This is the remaining investment credit, which will reduce the cost of services collected from ratepayers by a ratable portion over the investment's regulatory life. No definition available.
|
| X | ||||||||||
- Definition Energy related inventory, fuel oil, gas and materials and supplies, cost No definition available.
|
| X | ||||||||||
- Definition Tangible assets that are held by an entity for use in the production or supply of utilities and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. No definition available.
|
| X | ||||||||||
- Definition Non-Utility Property, Net No definition available.
|
| X | ||||||||||
- Definition Provision for injuries and damages. No definition available.
|
| X | ||||||||||
- Definition System Benefits Charge Liability, Current No definition available.
|
| X | ||||||||||
- Definition Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of receivable reflecting the cost incurred on uncompleted contracts in excess of related billings which is expected to be collected within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The current portion of money or property received from customers which is either to be returned upon satisfactory contract completion or applied to customer receivables in accordance with the terms of the contract or the understandings. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership, due within 1 year (or 1 business cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of payable due to an entity that is affiliated with the reporting entity by means of direct or indirect ownership. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of obligation due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Sum of the carrying values as of the balance sheet date of the portions of long-term notes payable due within one year or the operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of current assets classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of other miscellaneous assets expected to be realized or consumed after one year or normal operating cycle, if longer. No definition available.
|
| X | ||||||||||
- Definition Amount of noncurrent assets classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of unearned revenue or income classified as other, expected to be taken into income after one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of liabilities classified as other, due within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount due from parties in nontrade transactions, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of asset related to consideration paid in advance for costs that provide economic benefits within a future period of one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Period end book value of accumulated depreciation on property, plant and equipment (PPE) that is owned by the regulated operations of the public utility. No definition available.
|
| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to regulated assets common to business units. No definition available.
|
| X | ||||||||||
- Definition Period end amount of construction work in progress in public utility. No definition available.
|
| X | ||||||||||
- Definition Period end amount of total net PPE. No definition available.
|
| X | ||||||||||
- Definition Period end amount of total gross PPE. No definition available.
|
| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to transmission and distribution owned by public utility. No definition available.
|
| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Carrying value as of the balance sheet date of obligations incurred and payable for statutory income, sales, use, payroll, excise, real, property and other taxes. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Accounts receivable - customers, allowance for uncollectible accounts | $ 63 | $ 69 |
| Other receivables, allowance for uncollectible accounts | 8 | 14 |
| Non-utility property, accumulated depreciation | 201 | 140 |
| Intangible assets, accumulated amortization | 15 | 6 |
| CECONY | ||
| Accounts receivable - customers, allowance for uncollectible accounts | 58 | 65 |
| Other receivables, allowance for uncollectible accounts | 7 | 13 |
| Non-utility property, accumulated depreciation | $ 25 | $ 25 |
| X | ||||||||||
- Definition Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of valuation allowance for receivables classified as other, due within one year or the normal operating cycle, if longer. No definition available.
|
| X | ||||||||||
- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Definition Adjustments to Additional Paid in Capital, Contributions by Parent No definition available.
|
| X | ||||||||||
- Definition Stock Issued During Period, Shares, Dividend reinvestment and Employee Stock Purchase Plan No definition available.
|
| X | ||||||||||
- Definition Stock Issued During Period Value Dividend Reinvestment And Employee Stock Purchase Plan, Net of Repurchases No definition available.
|
| X | ||||||||||
- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Net Increase or Decrease in balance of noncontrolling interest in the subsidiary during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of new stock issued during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans. No definition available.
|
| X | ||||||||||
- Definition Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Gross value of stock (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Stock issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans. No definition available.
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Definition Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax And Reclassification Adjustment No definition available.
|
| X | ||||||||||
- Definition Total value of common stock equity No definition available.
|
| X | ||||||||||
- Definition Common stock equity before accumulated comprehensive income loss. No definition available.
|
| X | ||||||||||
- Definition Common Stock Equity Shares No definition available.
|
| X | ||||||||||
- Definition Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Definition This element represents the total consolidated (as applicable) capitalization of the entity which is comprised of its long-term debt and equity instruments. The table may be detailed by subsidiary (legal entity) and include information by type of debt or equity detailed by instrument. No definition available.
|
| X | ||||||||||
- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Contractual interest rate for funds borrowed, under the debt agreement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after accumulated amortization, of debt discount. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
| General | General These combined notes accompany and form an integral part of the separate consolidated financial statements of each of the two separate registrants: Consolidated Edison, Inc. and its subsidiaries (Con Edison) and Consolidated Edison Company of New York, Inc. and its subsidiaries (CECONY). CECONY is a subsidiary of Con Edison and as such its financial condition and results of operations and cash flows, which are presented separately in the CECONY consolidated financial statements, are also consolidated, along with those of Orange and Rockland Utilities, Inc. (O&R), Con Edison Clean Energy Businesses, Inc. (together with its subsidiaries, the Clean Energy Businesses) and Con Edison Transmission, Inc. (together with its subsidiaries, Con Edison Transmission) in Con Edison’s consolidated financial statements. The term “Utilities” is used in these notes to refer to CECONY and O&R. As used in these notes, the term “Companies” refers to Con Edison and CECONY and, except as otherwise noted, the information in these combined notes relates to each of the Companies. However, CECONY makes no representation as to information relating to Con Edison or the subsidiaries of Con Edison other than itself. Con Edison has two regulated utility subsidiaries: CECONY and O&R. CECONY provides electric service and gas service in New York City and Westchester County. The company also provides steam service in parts of Manhattan. O&R, along with its regulated utility subsidiary, provides electric service in southeastern New York and northern New Jersey and gas service in southeastern New York. Con Edison Clean Energy Businesses, Inc. has three subsidiaries: Consolidated Edison Development, Inc. (Con Edison Development), a company that develops, owns and operates renewable and energy infrastructure projects; Consolidated Edison Energy, Inc. (Con Edison Energy), a company that provides energy-related products and services to wholesale customers; and Consolidated Edison Solutions, Inc. (Con Edison Solutions), a company that provides energy-related products and services to retail customers. Con Edison Transmission, Inc. invests in electric transmission facilities through its subsidiary, Consolidated Edison Transmission, LLC (CET Electric), and invests in gas pipeline and storage facilities through its subsidiary Con Edison Gas Pipeline and Storage, LLC (CET Gas). See Note U. |
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Summary of Significant Accounting Policies |
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| Accounting Policies [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Significant Accounting Policies | Summary of Significant Accounting Policies Principles of Consolidation The Companies’ consolidated financial statements include the accounts of their respective majority-owned subsidiaries, and variable interest entities (see Note Q), as required. All intercompany balances and transactions have been eliminated. Accounting Policies The accounting policies of Con Edison and its subsidiaries conform to generally accepted accounting principles in the United States of America (GAAP). For the Utilities, these accounting principles include the accounting rules for regulated operations and the accounting requirements of the Federal Energy Regulatory Commission (FERC) and the state regulators having jurisdiction. The accounting rules for regulated operations specify the economic effects that result from the causal relationship of costs and revenues in the rate-regulated environment and how these effects are to be accounted for by a regulated enterprise. Revenues intended to cover some costs may be recorded either before or after the costs are incurred. If regulation provides assurance that incurred costs will be recovered in the future, these costs would be recorded as deferred charges or “regulatory assets” under the accounting rules for regulated operations. If revenues are recorded for costs that are expected to be incurred in the future, these revenues would be recorded as deferred credits or “regulatory liabilities” under the accounting rules for regulated operations. The Utilities’ principal regulatory assets and liabilities are detailed in Note B. The Utilities are receiving or being credited with a return on all of their regulatory assets for which a cash outflow has been made, and are paying or being charged with a return on all of their regulatory liabilities for which a cash inflow has been received. The Utilities’ regulatory assets and liabilities will be recovered from customers, or applied for customer benefit, in accordance with rate provisions approved by the applicable state regulators. Other significant accounting policies of the Companies are referenced below in this Note A and in the notes that follow. Plant and Depreciation Utility Plant Utility plant is stated at original cost. The cost of repairs and maintenance is charged to expense and the cost of betterments is capitalized. The capitalized cost of additions to utility plant includes indirect costs such as engineering, supervision, payroll taxes, pensions, other benefits and an allowance for funds used during construction (AFUDC). The original cost of property is charged to expense over the estimated useful lives of the assets. Upon retirement, the original cost of property is charged to accumulated depreciation. See Note R. Rates used for AFUDC include the cost of borrowed funds and a reasonable rate of return on the Utilities’ own funds when so used, determined in accordance with regulations of the FERC or the state public utility regulatory authority having jurisdiction. The rate is compounded semiannually, and the amounts applicable to borrowed funds are treated as a reduction of interest charges, while the amounts applicable to the Utilities’ own funds are credited to other income (deductions). The AFUDC rates for CECONY were 5.5 percent, 4.7 percent and 4.4 percent for 2017, 2016 and 2015, respectively. The AFUDC rates for O&R were 2.5 percent, 3.5 percent and 0.4 percent for 2017, 2016 and 2015, respectively. The Utilities generally compute annual charges for depreciation using the straight-line method for financial statement purposes, with rates based on average service lives and net salvage factors. The average depreciation rates for CECONY were 3.1 percent for 2017, 2016 and 2015. The average depreciation rates for O&R were 2.9 percent for 2017 and 2016 and 3.0 percent for 2015. The estimated lives for utility plant for CECONY range from 5 to 95 years for electric, 5 to 100 years for gas, 5 to 80 years for steam and 5 to 55 years for general plant. For O&R, the estimated lives for utility plant range from 5 to 75 years for electric and gas and 5 to 50 years for general plant. At December 31, 2017 and 2016, the capitalized cost of the Companies’ utility plant, net of accumulated depreciation, was as follows:
Under the Utilities’ rate plans, the aggregate annual depreciation allowance for the period ended December 31, 2017 was $1,253 million, including $1,184 million under CECONY’s electric, gas and steam rate plans that have been approved by the New York State Public Service Commission (NYSPSC). Non–Utility Plant Non-utility plant is stated at original cost. For Con Edison, non–utility plant consists primarily of the Clean Energy Businesses’ renewable electric production and gas storage. For the Utilities, non–utility plant consists of land and conduit for telecommunication use. Depreciation on these assets is computed using the straight-line method for financial statement purposes over their estimated useful lives, which range from 3 to 30 years. Goodwill Con Edison tests goodwill for impairment at least annually or whenever there is a triggering event. There is an option to first make a qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount before applying a two–step, quantitative goodwill impairment test. Con Edison has elected to perform the qualitative assessment for substantially all of its goodwill and, if needed, applies the two-step quantitative approach. The first step of the quantitative goodwill impairment test compares the estimated fair value of a reporting unit with its carrying value, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying value, goodwill of the reporting unit is considered not impaired. If the carrying value exceeds the estimated fair value of the reporting unit, the second step is performed to measure the amount of impairment loss, if any. The second step requires a calculation of the implied fair value of goodwill. In 2017, Con Edison recorded no impairment charge on goodwill. See Note K. Long–Lived and Intangible Assets Con Edison evaluates the impairment of long-lived assets and intangible assets with definite lives, based on projections of undiscounted future cash flows, whenever events or changes in circumstances indicate that the carrying amounts of such assets may not be recoverable. In the event an evaluation indicates that such cash flows cannot be expected to be sufficient to fully recover the assets, the assets are written down to their estimated fair value. In 2015, Con Edison recorded a $5 million impairment charge on the assets held for sale of Pike County Light & Power Company (Pike), a former O&R subsidiary that was sold in August 2016 (see Note U). No impairment charges on long-lived assets were recognized in 2017 or 2016. No impairment charges on intangible assets with definite lives were recognized in 2017, 2016, or 2015. For information about the Companies' intangible assets, see Note K. Revenues The Utilities and Con Edison Solutions, until the sale of its retail electric supply business in September 2016 (see Note U), recognize revenues as energy is delivered to customers. The Utilities accrue and Con Edison Solutions accrued revenues at the end of each month for estimated energy not yet billed to customers. The Utilities defer over a 12–month period net interruptible gas revenues, other than those authorized by the NYSPSC to be retained by the Utilities, for refund to firm gas sales and transportation customers. Con Edison Development recognizes revenue for the sale of energy from renewable electric production projects as energy is generated and billed to counterparties. Con Edison Development accrues revenues at the end of each month for energy not yet billed to counterparties. Con Edison Energy recognizes revenue as energy is delivered and services are provided for managing energy supply assets leased from others and managing the dispatch, fuel requirements and risk management activities for generating plants and merchant transmission in the northeastern United States. Con Edison Solutions recognizes revenue for providing energy-efficiency services to government and commercial customers, and Con Edison Development recognizes revenue for the engineering, procurement and construction of Upton 2, under the percentage-of-completion method of revenue recognition. Sales and profits on each percentage-of-completion contract are recorded based on the ratio of actual cumulative costs incurred to the total estimated costs at completion of the contract, multiplied by the total estimated contract revenue, less cumulative sales recognized in prior periods (the ‘‘cost-to-cost’’ method). The impact of revisions of contract estimates, which may result from contract modifications, performance or other reasons, are recognized on a cumulative catch-up basis in the period in which the revisions are made. Unbilled contract revenues were $58 million and $21 million as of December 31, 2017 and 2016, respectively, and represent accumulated incurred costs and earned profits on contracts (revenue arrangements), which have been recorded as revenues, but have not yet been billed to customers. Substantially all unbilled contract revenues are expected to be collected within one year. Unbilled contract revenues arise from the cost-to-cost method of revenue recognition. Unbilled contract revenues from fixed-price type contracts are converted to billed receivables when amounts are invoiced to customers according to contractual billing terms, which generally occur when deliveries or other performance milestones are completed. Unearned revenue, which reflects a liability for billings to customers in excess of earned revenue was $87 million and $2 million as of December 31, 2017 and 2016, respectively. Revenues recorded as energy is delivered, generated or services provided and billed to customers are recorded in accounts receivable – customers. Con Edison's and the Utilities' accounts receivable – customers balance also reflects the Utilities' purchase of receivables from energy service companies to support retail choice programs. Accrued revenues not yet billed to customers are recorded as accrued unbilled revenues. CECONY’s electric and gas rate plans and O&R’s New York electric and gas rate plans each contain a revenue decoupling mechanism under which the company’s actual energy delivery revenues are compared with the authorized delivery revenues and the difference accrued, with interest, for refund to, or recovery from, customers, as applicable. See “Rate Plans” in Note B. The NYSPSC requires utilities to record gross receipts tax revenues and expenses on a gross income statement presentation basis (i.e., included in both revenue and expense). The recovery of these taxes is generally provided for in the revenue requirement within each of the respective NYSPSC approved rate plans. Total excise taxes (inclusive of gross receipts taxes) recorded in operating revenues were as follows:
For information about changes to the accounting rules for revenue recognition, see Note T. Recoverable Energy Costs The Utilities generally recover all of their prudently incurred fuel, purchased power and gas costs, including hedging gains and losses, in accordance with rate provisions approved by the applicable state public utility regulators. If the actual energy supply costs for a given month are more or less than the amounts billed to customers for that month, the difference in most cases is recoverable from or refundable to customers. Differences between actual and billed electric and steam supply costs and costs of its electric demand management programs are generally deferred for charge or refund to customers during the next billing cycle (normally within one or two months). For the Utilities’ gas costs, differences between actual and billed gas costs during the 12–month period ending each August are charged or refunded to customers during a subsequent 12–month period. New York Independent System Operator (NYISO) The Utilities purchase electricity through the wholesale electricity market administered by the NYISO. The difference between purchased power and related costs initially billed to the Utilities by the NYISO and the actual cost of power subsequently calculated by the NYISO is refunded by the NYISO to the Utilities, or paid to the NYISO by the Utilities. The reconciliation payments or receipts are recoverable from or refundable to the Utilities’ customers. Certain other payments to or receipts from the NYISO are also subject to reconciliation, with shortfalls or amounts in excess of specified rate allowances recoverable from or refundable to customers. These include proceeds from the sale through the NYISO of transmission rights on CECONY’s transmission system (transmission congestion contracts or TCCs). Temporary Cash Investments Temporary cash investments are short-term, highly–liquid investments that generally have maturities of three months or less at the date of purchase. They are stated at cost, which approximates market. The Companies consider temporary cash investments to be cash equivalents. Investments Investments consist primarily of the investments of Con Edison Transmission and the Clean Energy Businesses that are accounted for under the equity method, and the fair value of the Utilities’ supplemental retirement income plan and deferred income plan assets. The following investment assets are included in the Companies' consolidated balance sheets at December 31, 2017 and 2016:
Pension and Other Postretirement Benefits The accounting rules for retirement benefits require an employer to recognize an asset or liability for the overfunded or underfunded status of its pension and other postretirement benefit plans. For a pension plan, the asset or liability is the difference between the fair value of the plan’s assets and the projected benefit obligation. For any other postretirement benefit plan, the asset or liability is the difference between the fair value of the plan’s assets and the accumulated postretirement benefit obligation. The accounting rules generally require employers to recognize all unrecognized prior service costs and credits and unrecognized actuarial gains and losses in accumulated other comprehensive income/(loss) (OCI), net of tax. Such amounts will be adjusted as they are subsequently recognized as components of total periodic benefit cost or income pursuant to the current recognition and amortization provisions. For the Utilities’ pension and other postretirement benefit plans, regulatory accounting treatment is generally applied in accordance with the accounting rules for regulated operations. Unrecognized prior service costs or credits and unrecognized actuarial gains and losses are recorded to regulatory assets or liabilities, rather than OCI. See Notes E and F. The total periodic benefit costs are recognized in accordance with the accounting rules for retirement benefits. Investment gains and losses are recognized in expense over a 15–year period and other actuarial gains and losses are recognized in expense over a 10–year period, subject to the deferral provisions in the rate plans. In accordance with the Statement of Policy issued by the NYSPSC and its current electric, gas and steam rate plans, CECONY defers for payment to or recovery from customers the difference between such expenses and the amounts for such expenses reflected in rates. Generally, O&R also defers such difference pursuant to its rate plans. See Note B. The Companies calculate the expected return on pension and other postretirement benefit plan assets by multiplying the expected rate of return on plan assets by the market-related value (MRV) of plan assets at the beginning of the year, taking into consideration anticipated contributions and benefit payments that are to be made during the year. The accounting rules allow the MRV of plan assets to be either fair value or a calculated value that recognizes changes in fair value in a systematic and rational manner over not more than five years. The Companies use a calculated value when determining the MRV of the plan assets that adjusts for 20 percent of the difference between fair value and expected MRV of plan assets. This calculated value has the effect of stabilizing variability in assets to which the Companies apply the expected return. Federal Income Tax In accordance with accounting rules for income taxes, the Companies have recorded an accumulated deferred federal income tax liability at current tax rates for temporary differences between the book and tax basis of assets and liabilities. In accordance with rate plans, the Utilities have recovered amounts from customers for a portion of the tax liability they will pay in the future as a result of the reversal or “turn-around” of these temporary differences. As to the remaining deferred tax liability, the Utilities had established regulatory assets for the net revenue requirements to be recovered from customers for the related future tax expense pursuant to the NYSPSC's 1993 Policy Statement approving accounting procedures consistent with accounting rules for income taxes and providing assurances that these future increases in taxes will be recoverable in rates. Upon enactment of the Tax Cuts and Jobs Act of 2017 on December 22, 2017 (the TCJA), the Companies re-measured their deferred tax assets and liabilities based upon the 21 percent corporate income tax rate under the TCJA. As a result, Con Edison decreased its net deferred tax liabilities by $5,312 million (including $4,781 million for CECONY), recognized net income of $259 million, decreased its regulatory asset for future income tax by $1,250 million (including $1,182 million for CECONY), decreased its regulatory asset for revenue taxes by $90 million (including $86 million for CECONY), and accrued a regulatory liability for future income tax of $3,713 million (including $3,513 million for CECONY). See “Other Regulatory Matters” and “Regulatory Assets and Liabilities” in Note B and Note L. Accumulated deferred investment tax credits are amortized ratably over the lives of the related properties and applied as a reduction to future federal income tax expense. Con Edison and its subsidiaries file a consolidated federal income tax return. The consolidated income tax liability is allocated to each member of the consolidated group using the separate return method. Each member pays or receives an amount based on its own taxable income or loss in accordance with a consolidated tax allocation agreement. Tax loss and tax credit carryforwards are allocated among members in accordance with consolidated tax return regulations. State Income Tax Con Edison and its subsidiaries file a combined New York State Corporation Business Franchise Tax Return. Similar to a federal consolidated income tax return, the income of all entities in the combined group is subject to New York State taxation, after adjustments for differences between federal and New York law and apportionment of income among the states in which the company does business. Each member’s share of the New York State tax is based on its own New York State taxable income or loss. Research and Development Costs Research and development costs are charged to operating expenses as incurred. Research and development costs were as follows:
Reclassification Certain prior year amounts have been reclassified to conform with the current year presentation. Earnings Per Common Share Con Edison presents basic and diluted earnings per share on the face of its consolidated income statement. Basic earnings per share (EPS) are calculated by dividing earnings available to common shareholders (“Net income” on Con Edison’s consolidated income statement) by the weighted average number of Con Edison common shares outstanding during the period. In the calculation of diluted EPS, weighted average shares outstanding are increased for additional shares that would be outstanding if potentially dilutive securities were converted to common stock. Potentially dilutive securities for Con Edison consist of restricted stock units and deferred stock units for which the average market price of the common shares for the period was greater than the exercise price. See Note M. Basic and diluted EPS for Con Edison are calculated as follows:
Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Changes in Accumulated Other Comprehensive Income/(Loss) by Component Changes to accumulated other comprehensive income/(loss) (OCI) for Con Edison and CECONY are as follows:
(b) For the portion of unrecognized pension and other postretirement benefit costs relating to the Utilities, costs are recorded into, and amortized out of, regulatory assets instead of OCI. The net actuarial losses and prior service costs recognized during the period are included in the computation of total periodic pension and other postretirement benefit cost. See Notes E and F. |
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- Definition The entire disclosure for all significant accounting policies of the reporting entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Regulatory Matters |
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| Regulated Operations [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Regulatory Matters | Regulatory Matters Rate Plans The Utilities provide service to New York customers according to the terms of tariffs approved by the NYSPSC. Tariffs for service to customers of Rockland Electric Company (RECO), O&R’s New Jersey regulated utility subsidiary, are approved by the New Jersey Board of Public Utilities (NJBPU). The tariffs include schedules of rates for service that limit the rates charged by the Utilities to amounts that recover from their customers costs approved by the regulator, including capital costs, of providing service to customers as defined by the tariff. The tariffs implement rate plans adopted by state utility regulators in rate orders issued at the conclusion of rate proceedings. Pursuant to the Utilities’ rate plans, there generally can be no change to the charges to customers during the respective terms of the rate plans other than specified adjustments provided for in the rate plans. The Utilities’ rate plans each cover specified periods, but rates determined pursuant to a plan generally continue in effect until a new rate plan is approved by the state utility regulator. Common provisions of the Utilities’ New York rate plans include: Recoverable energy costs that allow the Utilities to recover on a current basis the costs for the energy they supply with no mark-up to their full-service customers. Cost reconciliations that reconcile pension and other postretirement benefit costs, environmental remediation costs, property taxes, variable rate tax-exempt debt and certain other costs to amounts reflected in delivery rates for such costs. In addition, changes in the Utilities' costs not reflected in rates, in excess of certain amounts, resulting from changes in tax or other law, rule, regulation, order, or other requirement or interpretation are deferred as a regulatory asset or regulatory liability to be reflected in the Utilities' next rate plan or in a manner to be determined by the NYSPSC. See "Other Regulatory Matters," below. Also, the Utilities generally retain the right to petition for recovery or accounting deferral of extraordinary and material cost increases and provision is sometimes made for the utility to retain a share of cost reductions, for example, property tax refunds. Revenue decoupling mechanisms that reconcile actual energy delivery revenues to the authorized delivery revenues approved by the NYSPSC. The difference is accrued with interest for refund to, or recovery from customers, as applicable. Earnings sharing that require the Utilities to defer for customer benefit a portion of earnings over specified rates of return on common equity. There is no symmetric mechanism for earnings below specified rates of return on common equity. Negative revenue adjustments for failure to meet certain performance standards relating to service, reliability, safety and other matters. Positive revenue adjustments for achievement of performance standards related to achievement of clean energy goals, safety and other matters. Net utility plant reconciliations that require deferral as a regulatory liability of the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates. There is generally no symmetric mechanism if actual average net utility plant balances are more than amounts reflected in rates. Rate base, as reflected in the rate plans, is, in general, the sum of the Utilities’ net plant, working capital and certain regulatory assets less deferred taxes and certain regulatory liabilities. For each rate plan, the NYSPSC uses a forecast of the average rate base for each year that new rates would be in effect (“rate year”). Weighted average cost of capital is determined based on the authorized common equity ratio, return on common equity, cost of long-term debt and customer deposits reflected in each rate plan. For each rate plan, the revenues designed to provide the utility a return on invested capital for each rate year are determined by multiplying each utility rate base by its pre–tax weighted average cost of capital. The Utilities’ actual return on common equity will reflect their actual operations for each rate year, and may be more or less than the authorized return on equity reflected in their rate plans (and if more, may be subject to earnings sharing). The following tables contain a summary of the Utilities’ rate plans:
In January 2018, O&R filed a request with the NYSPSC for an increase in the rates it charges for electric service rendered in New York, effective January 1, 2019, of $20.3 million. The filing reflects a return on common equity of 9.75 percent and a common equity ratio of 48 percent. The filing proposes continuation of the provisions with respect to recovery from customers of the cost of purchased power, and the reconciliation of actual expenses allocable to the electric business to the amounts for such costs reflected in electric rates for storm costs, pension and other postretirement benefit costs, environmental remediation and property taxes.
In January 2018, O&R filed a request with the NYSPSC for an increase in the rates it charges for gas service rendered in New York, effective January 1, 2019, of $4.5 million. The filing reflects a return on common equity of 9.75 percent and a common equity ratio of 48 percent. The filing proposes continuation of the provisions with respect to recovery from customers of the cost of purchased gas, and the reconciliation of actual expenses allocable to the gas business to the amounts for such costs reflected in gas rates for pension and other postretirement benefit costs, environmental remediation and property taxes.
In November 2017, FERC approved a September 2017 settlement agreement among RECO, the New Jersey Division of Rate Counsel and the NJBPU that increases RECO's annual transmission revenue requirement from $11.8 million to $17.7 million, effective April 2017. The revenue requirement reflects a return on common equity of 10.0 percent. Other Regulatory Matters In August and November 2017, the NYSPSC issued orders in its proceeding investigating an April 21, 2017 Metropolitan Transportation Authority (MTA) subway power outage. The orders indicated that the investigation determined that the outage was caused by a failure of CECONY’s electricity supply to a subway station, which led to a loss of the subway signals, and that one of the secondary services to the MTA facility had been improperly rerouted and was not properly documented by the company. The orders also indicated that the loss of power to the subway station affected multiple subway lines and caused widespread delays across the subway system. Pursuant to the orders, the company is required to take certain actions, including inspecting, repairing and installing certain electrical equipment that serves the subway system, analyzing power supply and power quality events affecting the MTA’s signaling services, and filing monthly reports with the NYSPSC on all of the company's activities related to the subway system. In July 2017, the Chairman of the NYSPSC notified the company that the April 21, 2017 subway power outage incident will likely result in a prudence review of the reasonableness of CECONY's actions and conduct. The orders did not commence a prudence review. The company incurred costs related to this matter in 2017 of $65 million. Included in this amount is $15 million in capital and operating and maintenance costs reflected in the company's electric rate plan and $50 million deferred as a regulatory asset pursuant to the rate plan. The company, which plans to complete the required actions in 2018, expects to incur costs related to this matter in 2018 of $137 million. Included in this amount is $10 million in expected capital and operating and maintenance costs reflected in the rate plan and $127 million expected to be deferred as a regulatory asset pursuant to the rate plan. In December 2017, the NYSPSC issued an order initiating a proceeding to study the potential effects of the TCJA on the tax expenses and liabilities of New York State utilities and the regulatory treatment to preserve the resulting benefits for customers. In January 2018, the NJBPU issued an order initiating a proceeding to consider the TCJA. Upon enactment of the TCJA, CECONY, O&R and RECO re-measured their deferred tax assets and liabilities based upon the 21 percent corporate income tax rate under the TCJA. As a result, CECONY, O&R and RECO, decreased their net deferred tax liabilities by $4,781 million, $216 million and $45 million, respectively, decreased their regulatory asset for future income tax by $1,182 million, $51 million and $17 million, respectively, decreased their regulatory asset for revenue taxes by $86 million, $4 million and $0 million, respectively, and accrued regulatory liabilities for future income tax of $3,513 million, $161 million and $28 million, respectively. See Note L. In January 2018, the NYSPSC issued an order initiating a focused operations audit of the income tax accounting of certain utilities, including CECONY and O&R. See footnote (h) to the table under "CECONY – Electric," above. Regulatory Assets and Liabilities Regulatory assets and liabilities at December 31, 2017 and 2016 were comprised of the following items:
Unrecognized pension and other postretirement costs represent the net regulatory asset associated with the accounting rules for retirement benefits. See Note A. Revenue taxes represent the timing difference between taxes collected and paid by the Utilities to fund mass transportation. Deferred storm costs represent response and restoration costs, other than capital expenditures, in connection with Superstorm Sandy and other major storms that were deferred by the Utilities. Net electric deferrals represent the remaining unamortized balance of certain regulatory assets and liabilities of CECONY that were combined effective April 1, 2010 and are being amortized to income through March 31, 2018. Settlement of prudence proceeding represents the remaining amount to be credited to customers pursuant to a Joint Proposal, approved by the NYSPSC in April 2016, with respect to the prudence of certain CECONY expenditures and related matters. Settlement of gas proceedings represents the amount to be credited to customers pursuant to a settlement agreement approved by the NYSPSC in February 2017 related to CECONY’s practices of qualifying persons to perform plastic fusions on gas facilities and alleged violations of gas safety violations identified by the NYSPSC staff in its investigation of a March 2014 Manhattan explosion and fire (see Note H). The NYSPSC has authorized CECONY to accrue unbilled electric, gas and steam revenues. CECONY has deferred the net margin on the unbilled revenues for the future benefit of customers by recording a regulatory liability of $183 million and $145 million at December 31, 2017 and 2016, respectively, for the difference between the unbilled revenues and energy cost liabilities. Electricity Purchase Agreements The Utilities have electricity purchase agreements with non-utility generators and others for generating capacity. The Utilities recover their purchased power costs in accordance with provisions approved by the applicable state public utility regulators. See “Recoverable Energy Costs” in Note A. At December 31, 2017, the significant terms of the electricity purchase agreements with non-utility generators were as follows:
(a) A portion of this contract ended in 2017 and a portion ends in 2018. The Utilities also conducted auctions and have entered into various other electricity purchase agreements. Assuming performance by the parties to the electricity purchase agreements, the Utilities are obligated over the terms of the agreements to make capacity and other fixed payments. The future capacity and other fixed payments under the contracts are estimated to be as follows:
For energy delivered under most of the electricity purchase agreements, CECONY is obligated to pay variable prices. The company’s payments under the significant terms of the agreements for capacity, energy and other fixed payments in 2017, 2016 and 2015 were as follows:
(a) Contract term ended in 2017. (b) Contract term ended in 2016. (c) Contract term ended in 2015. |
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- Definition The entire disclosure for public utilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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Capitalization |
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| Debt Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Capitalization | Capitalization Common Stock At December 31, 2017 and 2016, Con Edison owned all of the issued and outstanding shares of common stock of the Utilities, the Clean Energy Businesses and Con Edison Transmission. CECONY owns 21,976,200 shares of Con Edison stock, which it purchased prior to 2001 in connection with Con Edison’s stock repurchase plan. CECONY presents in the financial statements the cost of the Con Edison stock it owns as a reduction of common shareholder’s equity. Capitalization of Con Edison The outstanding capitalization for each of the Companies is shown on its Consolidated Statement of Capitalization, and for Con Edison includes outstanding debt of the Utilities and the Clean Energy Businesses. Dividends In accordance with NYSPSC requirements, the dividends that the Utilities generally pay are limited to not more than 100 percent of their respective income available for dividends calculated on a two–year rolling average basis. Excluded from the calculation of “income available for dividends” are non-cash charges to income resulting from accounting changes or charges to income resulting from significant unanticipated events. The restriction also does not apply to dividends paid in order to transfer to Con Edison proceeds from major transactions, such as asset sales, or to dividends reducing each utility subsidiary’s equity ratio to a level appropriate to its business risk. Long-term Debt Long-term debt maturing in the period 2018-2022 is as follows:
CECONY has issued $450 million of tax–exempt debt through the New York State Energy Research and Development Authority (NYSERDA) that currently bear interest at a rate determined weekly and is subject to tender by bondholders for purchase by the company. The carrying amounts and fair values of long-term debt at December 31, 2017 and 2016 are:
Fair values of long-term debt have been estimated primarily using available market information. For Con Edison, $17,511 million and $636 million of the fair value of long-term debt at December 31, 2017 are classified as Level 2 and Level 3, respectively. For CECONY, $14,527 million and $636 million of the fair value of long-term debt at December 31, 2017 are classified as Level 2 and Level 3, respectively (see Note P). The $636 million of long-term debt classified as Level 3 is CECONY’s tax-exempt, auction-rate securities for which the market is highly illiquid and there is a lack of observable inputs. At December 31, 2017 and 2016, long–term debt of Con Edison included $915 million and $845 million, respectively, of non-recourse debt secured by the pledge of the applicable renewable energy production projects of the Clean Energy Businesses. At December 31, 2017 and 2016, long-term debt of Con Edison included $7 million and $11 million, respectively, of Transition Bonds issued in 2004 by O&R’s New Jersey utility subsidiary through a special purpose entity. Significant Debt Covenants The significant debt covenants under the financing arrangements for the Companies' debentures and Con Edison's notes include obligations to pay principal and interest when due and covenants not to consolidate with or merge into any other corporation unless certain conditions are met. In addition, Con Edison's notes include covenants that the company shall continue its utility business in New York City and shall not permit its ratio of consolidated debt to consolidated capital to exceed 0.675 to 1 and include cross default provisions with respect to other indebtedness of the company or its material subsidiaries having a then outstanding principal balance in excess of $100 million. The Companies' debentures have no cross default provisions. The tax–exempt financing arrangements of CECONY are subject to covenants for the debentures discussed above and the covenants discussed below. The Companies were in compliance with their significant debt covenants at December 31, 2017. The tax-exempt financing arrangements involved the issuance of uncollateralized promissory notes of CECONY to NYSERDA in exchange for the net proceeds of a like amount of tax–exempt bonds with substantially the same terms sold to the public by NYSERDA. The tax-exempt financing arrangements include covenants with respect to the tax–exempt status of the financing, including covenants with respect to the use of the facilities financed. The arrangements include provisions for the maintenance of liquidity and credit facilities, the failure to comply with which would, except as otherwise provided, constitute an event of default for the debt to which such provisions applied. The failure to comply with debt covenants would, except as otherwise provided, constitute an event of default for the debt to which such provisions applied. If an event of default were to occur, the principal and accrued interest on the debt to which such event of default applied and, in the case of the Con Edison notes, a make-whole premium might and, in the case of certain events of default would, become due and payable immediately. The liquidity and credit facilities currently in effect for the tax–exempt financing include covenants that the ratio of debt to total capital of CECONY will not at any time exceed 0.65 to 1 and that, subject to certain exceptions, CECONY will not mortgage, lien, pledge or otherwise encumber its assets. Certain of the facilities also include as events of default, defaults in payments of other debt obligations in excess of specified levels ($150 million or $100 million, depending on the facility) |
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- Definition Capitalization [Text Block] No definition available.
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- References No definition available.
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Short-Term Borrowing |
12 Months Ended |
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Dec. 31, 2017 | |
| Debt Disclosure [Abstract] | |
| Short-Term Borrowing | Short-Term Borrowing In December 2016, Con Edison and the Utilities entered into a credit agreement (Credit Agreement), under which banks are committed to provide loans and letters of credit on a revolving credit basis. The Credit Agreement expires in December 2022. There is a maximum of $2,250 million of credit available. The full amount is available to CECONY and $1,000 million (subject to increase up to $1,500 million) is available to Con Edison, including up to $1,200 million of letters of credit. The Credit Agreement supports the Companies’ commercial paper programs. The Companies have not borrowed under the Credit Agreement. At December 31, 2017, Con Edison had $577 million of commercial paper outstanding, of which $150 million was outstanding under CECONY’s program. The weighted average interest rate at December 31, 2017 was 1.8 percent for both Con Edison and CECONY. At December 31, 2016, Con Edison had $1,054 million of commercial paper outstanding of which $600 million was outstanding under CECONY’s program. The weighted average interest rate at December 31, 2016 was 1.0 percent for both Con Edison and CECONY. At December 31, 2017 and 2016, no loans were outstanding under the credit agreement (Credit Agreement). An immaterial amount and $2 million (including $2 million for CECONY) of letters of credit were outstanding under the Credit Agreement as of December 31, 2017 and 2016, respectively. The banks’ commitments under the Credit Agreement are subject to certain conditions, including that there be no event of default. The commitments are not subject to maintenance of credit rating levels or the absence of a material adverse change. Upon a change of control of, or upon an event of default by one of the Companies, the banks may terminate their commitments with respect to that company, declare any amounts owed by that company under the Credit Agreement immediately due and payable and require that company to provide cash collateral relating to the letters of credit issued for it under the Credit Agreement. Events of default include the exceeding at any time of a ratio of consolidated debt to consolidated total capital of 0.65 to 1 (at December 31, 2017 this ratio was 0.51 to 1 for Con Edison and 0.52 to 1 for CECONY); having liens on its assets in an aggregate amount exceeding five percent of its consolidated total capital, subject to certain exceptions; and the failure, following any applicable notice period, to meet certain other customary covenants. Interest and fees charged for the revolving credit facilities and any loans made or letters of credit issued under the Credit Agreement reflect the Companies’ respective credit ratings. The Companies were in compliance with their covenants at December 31, 2017. See Note S for information about short-term borrowing between related parties. |
| X | ||||||||||
- References No definition available.
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- Definition The entire disclosure for short-term debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Pension Benefits |
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| Retirement Benefits [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pension Benefits | Pension Benefits Con Edison maintains a tax-qualified, non-contributory pension plan that covers substantially all employees of CECONY, O&R, Con Edison Transmission and certain employees of the Clean Energy Businesses. The plan is designed to comply with the Internal Revenue Code and the Employee Retirement Income Security Act of 1974. In addition, Con Edison maintains additional non–qualified supplemental pension plans. Total Periodic Benefit Cost The components of the Companies’ total periodic benefit costs for 2017, 2016 and 2015 were as follows:
(a) Relates to an increase in CECONY’s pension obligation of $45 million from a 1999 special retirement program. Funded Status The funded status at December 31, 2017, 2016 and 2015 was as follows:
The increase in the pension plan’s fair value of plan assets was the primary cause of the decreased pension liability at Con Edison and CECONY of $361 million and $340 million, respectively, compared with December 31, 2016. For Con Edison, this decrease in pension liability corresponds with a decrease to regulatory assets of $368 million for unrecognized net losses and unrecognized prior service costs associated with the Utilities consistent with the accounting rules for regulated operations, a credit to OCI of $4 million (net of taxes) for the unrecognized net losses, and an immaterial change to OCI (net of taxes) for the unrecognized prior service costs associated with the Clean Energy Businesses, Con Edison Transmission, and RECO. For CECONY, the decrease in pension liability corresponds with a decrease to regulatory assets of $353 million for unrecognized net losses and unrecognized prior service costs consistent with the accounting rules for regulated operations, a credit to OCI of $1 million (net of taxes) for unrecognized net losses, and an immaterial change to OCI (net of taxes) for the unrecognized prior service costs associated with the Clean Energy Businesses and Con Edison Transmission. A portion of the unrecognized net loss and prior service cost for the pension plan, equal to $689 million and $(17) million, respectively, will be recognized from accumulated OCI and the regulatory asset into net periodic benefit cost over the next year for Con Edison. Included in these amounts are $654 million and $(19) million, respectively, for CECONY. At December 31, 2017 and 2016, Con Edison’s investments include $330 million and $273 million, respectively, held in external trust accounts for benefit payments pursuant to the supplemental retirement plans. Included in these amounts for CECONY were $301 million and $246 million, respectively. See Note P. The accumulated benefit obligations for the supplemental retirement plans for Con Edison and CECONY were $331 million and $297 million as of December 31, 2017 and $303 million and $268 million as of December 31, 2016, respectively. Assumptions The actuarial assumptions were as follows:
The expected return assumption reflects anticipated returns on the plan’s current and future assets. The Companies’ expected return was based on an evaluation of the current environment, market and economic outlook, relationships between the economy and asset class performance patterns, and recent and long-term trends in asset class performance. The projections were based on the plan’s target asset allocation. Discount Rate Assumption To determine the assumed discount rate, the Companies use a model that produces a yield curve based on yields on selected highly rated (Aa or higher by either Moody’s or Standard & Poor’s) corporate bonds. Bonds with insufficient liquidity, bonds with questionable pricing information and bonds that are not representative of the overall market are excluded from consideration. For example, the bonds used in the model cannot be callable (with the exception of "make whole" callable bonds), and the amount of the bond issue outstanding must be in excess of $50 million. The spot rates defined by the yield curve and the plan’s projected benefit payments are used to develop a weighted average discount rate. Expected Benefit Payments Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years:
Expected Contributions Based on estimates as of December 31, 2017, the Companies expect to make contributions to the pension plans during 2018 of $473 million (of which $435 million is to be contributed by CECONY). The Companies’ policy is to fund the total periodic benefit cost of the qualified plan to the extent tax deductible and to also contribute to the non-qualified supplemental plans. Plan Assets The asset allocations for the pension plan at the end of 2017, 2016 and 2015, and the target allocation for 2018 are as follows:
Con Edison has established a pension trust for the investment of assets to be used for the exclusive purpose of providing retirement benefits to participants and beneficiaries and payment of plan expenses. Pursuant to resolutions adopted by Con Edison’s Board of Directors, the Management Development and Compensation Committee of the Board of Directors (the Committee) has general oversight responsibility for Con Edison’s pension and other employee benefit plans. The pension plan’s named fiduciaries have been granted the authority to control and manage the operation and administration of the plans, including overall responsibility for the investment of assets in the trust and the power to appoint and terminate investment managers. The investment objectives of the Con Edison pension plan are to maintain a level and form of assets adequate to meet benefit obligations to participants, to achieve the expected long-term total return on the trust assets within a prudent level of risk and maintain a level of volatility that is not expected to have a material impact on the company’s expected contribution and expense or the company’s ability to meet plan obligations. The assets of the plan have no significant concentration of risk in one country (other than the United States), industry or entity. The strategic asset allocation is intended to meet the objectives of the pension plan by diversifying its funds across asset classes, investment styles and fund managers. An asset/liability study typically is conducted every few years to determine whether the current strategic asset allocation continues to represent the appropriate balance of expected risk and reward for the plan to meet expected liabilities. Each study considers the investment risk of the asset allocation and determines the optimal asset allocation for the plan. The target asset allocation for 2018 reflects the results of such a study conducted in 2016. Individual fund managers operate under written guidelines provided by Con Edison, which cover such areas as investment objectives, performance measurement, permissible investments, investment restrictions, trading and execution, and communication and reporting requirements. Con Edison management regularly monitors, and the named fiduciaries review and report to the Committee regarding, asset class performance, total fund performance, and compliance with asset allocation guidelines. Management changes fund managers and rebalances the portfolio as appropriate. At the direction of the named fiduciaries, such changes are reported to the Committee. Assets measured at fair value on a recurring basis are summarized below as defined by the accounting rules for fair value measurements (see Note P). The fair values of the pension plan assets at December 31, 2017 by asset category are as follows:
The fair values of the pension plan assets at December 31, 2016 by asset category are as follows:
The Companies also offer a defined contribution savings plan that covers substantially all employees and made contributions to the plan as follows:
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure for pension and other postretirement benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Other Postretirement Benefits |
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| Retirement Benefits [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Postretirement Benefits | Other Postretirement Benefits The Utilities and Con Edison Transmission currently have contributory comprehensive hospital, medical and prescription drug programs for eligible retirees, their dependents and surviving spouses. CECONY also has a contributory life insurance program for bargaining unit employees and provides basic life insurance benefits up to a specified maximum at no cost to certain retired management employees. O&R has a non-contributory life insurance program for retirees. Certain employees of the Clean Energy Businesses and Con Edison Transmission are eligible to receive benefits under these programs. Total Periodic Benefit Cost The components of the Companies’ total periodic postretirement benefit costs for 2017, 2016 and 2015 were as follows:
Funded Status The funded status of the programs at December 31, 2017, 2016 and 2015 were as follows:
The increase in the fair value of plan assets was the primary cause of the decreased liability for other postretirement benefits at Con Edison and CECONY of $43 million and $64 million, respectively, compared with December 31, 2016. For Con Edison, this decreased liability corresponds with an increase to regulatory liabilities of $11 million for unrecognized net losses and unrecognized prior service costs associated with the Utilities consistent with the accounting rules for regulated operations, a debit to OCI of $3 million (net of taxes) for the unrecognized net losses and an immaterial change to OCI (net of taxes) for the unrecognized prior service costs associated with the Clean Energy Businesses, Con Edison Transmission, and RECO. For CECONY, the decrease in liability corresponds with an increase to regulatory liabilities of $32 million for unrecognized net losses and unrecognized prior service costs associated with the company consistent with the accounting rules for regulated operations, and an immaterial change to OCI (net of taxes) for the unrecognized net losses and unrecognized prior service costs associated with the Clean Energy Businesses and Con Edison Transmission. A portion of the unrecognized net losses and prior service costs for the other postretirement benefits, equal to $8 million and $(6) million, respectively, will be recognized from accumulated OCI and the regulatory asset into net periodic benefit cost over the next year for Con Edison. Included in these amounts are $1 million and $(2) million, respectively, for CECONY. Assumptions The actuarial assumptions were as follows:
Refer to Note E for descriptions of the basis for determining the expected return on assets, investment policies and strategies and the assumed discount rate. The health care cost trend rate used to determine net periodic benefit cost for the year ended December 31, 2017 was 5.80 percent, which is assumed to decrease gradually to 4.50 percent by 2024 and remain at that level thereafter. The health care cost trend rate used to determine benefit obligations as of December 31, 2017 was 5.60 percent, which is assumed to decrease gradually to 4.50 percent by 2024 and remain at that level thereafter. A one-percentage point change in the assumed health care cost trend rate would have the following effects at December 31, 2017:
Expected Benefit Payments Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years, net of receipt of governmental subsidies:
Expected Contributions Based on estimates as of December 31, 2017, Con Edison and CECONY expect to make a contribution of $7 million (substantially all of which is to be contributed by CECONY) to the other postretirement benefit plans in 2018. The Companies’ policy is to fund the total periodic benefit cost of the plans to the extent tax deductible. Plan Assets The asset allocations for CECONY’s other postretirement benefit plans at the end of 2017, 2016 and 2015, and the target allocation for 2018 are as follows:
Con Edison has established postretirement health and life insurance benefit plan trusts for the investment of assets to be used for the exclusive purpose of providing other postretirement benefits to participants and beneficiaries. Refer to Note E for a discussion of Con Edison’s investment policy for its benefit plans. The fair values of the plan assets at December 31, 2017 by asset category as defined by the accounting rules for fair value measurements (see Note P) are as follows:
The fair values of the plan assets at December 31, 2016 by asset category (see Note P) are as follows:
(a) - (f) Reference is made to footnotes (a) through (f) in the above table of other postretirement benefit plan assets at December 31, 2017 by asset category. |
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- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure for postemployment benefits, which may include supplemental unemployment benefits, obligations recognized for all types of benefits provided to former or inactive employees, their beneficiaries, and covered dependents after employment but before retirement. Disclosure may also include discussion that an obligation for postemployment benefits is not accrued in accordance with regulation only because the amount cannot be reasonably estimated. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Environmental Matters |
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| Environmental Remediation Obligations [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Environmental Matters | Environmental Matters Superfund Sites Hazardous substances, such as asbestos, polychlorinated biphenyls (PCBs) and coal tar, have been used or generated in the course of operations of the Utilities and their predecessors and are present at sites and in facilities and equipment they currently or previously owned, including sites at which gas was manufactured or stored. The Federal Comprehensive Environmental Response, Compensation and Liability Act of 1980 and similar state statutes (Superfund) impose joint and several liability, regardless of fault, upon generators of hazardous substances for investigation and remediation costs (which include costs of demolition, removal, disposal, storage, replacement, containment and monitoring) and natural resource damages. Liability under these laws can be material and may be imposed for contamination from past acts, even though such past acts may have been lawful at the time they occurred. The sites at which the Utilities have been asserted to have liability under these laws, including their manufactured gas plant sites and any neighboring areas to which contamination may have migrated, are referred to herein as “Superfund Sites.” For Superfund Sites where there are other potentially responsible parties and the Utilities are not managing the site investigation and remediation, the accrued liability represents an estimate of the amount the Utilities will need to pay to investigate and, where determinable, discharge their related obligations. For Superfund Sites (including the manufactured gas plant sites) for which one of the Utilities is managing the investigation and remediation, the accrued liability represents an estimate of the company’s share of the undiscounted cost to investigate the sites and, for sites that have been investigated in whole or in part, the cost to remediate the sites, if remediation is necessary and if a reasonable estimate of such cost can be made. Remediation costs are estimated in light of the information available, applicable remediation standards and experience with similar sites. The accrued liabilities and regulatory assets related to Superfund Sites at December 31, 2017 and 2016 were as follows:
Most of the accrued Superfund Site liability relates to sites that have been investigated, in whole or in part. However, for some of the sites, the extent and associated cost of the required remediation has not yet been determined. As investigations progress and information pertaining to the required remediation becomes available, the Utilities expect that additional liability may be accrued, the amount of which is not presently determinable but may be material. The Utilities are permitted to recover or defer as regulatory assets (for subsequent recovery through rates) prudently incurred site investigation and remediation costs. Environmental remediation costs incurred related to Superfund Sites at December 31, 2017 and 2016 were as follows:
Insurance and other third party recoveries received by Con Edison or CECONY were immaterial in 2017. Con Edison and CECONY received $1 million in insurance and other third party recoveries in 2016. Con Edison and CECONY estimate that in 2018 they will incur costs for remediation of approximately $47 million and $34 million, respectively. The Companies are unable to estimate the time period over which the remaining accrued liability will be incurred because, among other things, the required remediation has not been determined for some of the sites. In 2017, Con Edison and CECONY estimated that for their manufactured gas plant sites (including CECONY’s Astoria site), the aggregate undiscounted potential liability for the investigation and remediation of coal tar and/or other environmental contaminants could range up to $2.7 billion and $2.5 billion, respectively. These estimates were based on the assumption that there is contamination at all sites, including those that have not yet been fully investigated and additional assumptions about the extent of the contamination and the type and extent of the remediation that may be required. Actual experience may be materially different. Asbestos Proceedings Suits have been brought in New York State and federal courts against the Utilities and many other defendants, wherein a large number of plaintiffs sought large amounts of compensatory and punitive damages for deaths and injuries allegedly caused by exposure to asbestos at various premises of the Utilities. The suits that have been resolved, which are many, have been resolved without any payment by the Utilities, or for amounts that were not, in the aggregate, material to them. The amounts specified in all the remaining thousands of suits total billions of dollars; however, the Utilities believe that these amounts are greatly exaggerated, based on the disposition of previous claims. At December 31, 2017, Con Edison and CECONY have accrued their estimated aggregate undiscounted potential liabilities for these suits and additional suits that may be brought over the next 15 years as shown in the following table. These estimates were based upon a combination of modeling, historical data analysis and risk factor assessment. Courts have begun, and unless otherwise determined on appeal may continue, to apply different standards for determining liability in asbestos suits than the standard that applied historically. As a result, the Companies currently believe that there is a reasonable possibility of an exposure to loss in excess of the liability accrued for the suits. The Companies are unable to estimate the amount or range of such loss. In addition, certain current and former employees have claimed or are claiming workers’ compensation benefits based on alleged disability from exposure to asbestos. CECONY is permitted to defer as regulatory assets (for subsequent recovery through rates) costs incurred for its asbestos lawsuits and workers’ compensation claims. The accrued liability for asbestos suits and workers’ compensation proceedings (including those related to asbestos exposure) and the amounts deferred as regulatory assets for the Companies at December 31, 2017 and 2016 were as follows:
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- Definition The entire disclosure for environmental loss contingencies, such as presence of hazardous waste, relevant information from reports issued by regulators, and estimated costs to achieve compliance with regulatory requirements. This element may be used for all of an entity's disclosures about environmental loss contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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Other Material Contingencies |
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| Commitments and Contingencies Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other Material Contingencies | Other Material Contingencies Manhattan Explosion and Fire On March 12, 2014, two multi-use five-story tall buildings located on Park Avenue between 116th and 117th Streets in Manhattan were destroyed by an explosion and fire. CECONY had delivered gas to the buildings through service lines from a distribution main located below ground on Park Avenue. Eight people died and more than 50 people were injured. Additional buildings were also damaged. The National Transportation Safety Board (NTSB) investigated. The parties to the investigation included the company, the City of New York, the Pipeline and Hazardous Materials Safety Administration and the NYSPSC. In June 2015, the NTSB issued a final report concerning the incident, its probable cause and safety recommendations. The NTSB determined that the probable cause of the incident was (1) the failure of a defective fusion joint at a service tee (which joined a plastic service line to a plastic distribution main) installed by the company that allowed gas to leak from the distribution main and migrate into a building where it ignited and (2) a breach in a City sewer line that allowed groundwater and soil to flow into the sewer, resulting in a loss of support for the distribution main, which caused it to sag and overstressed the defective fusion joint. The NTSB also made safety recommendations, including recommendations to the company that addressed its procedures for the preparation and examination of plastic fusions, training of its staff on conditions for notifications to the City’s Fire Department and extension of its gas main isolation valve installation program. In February 2017, the NYSPSC approved a settlement agreement with the company related to the NYSPSC's investigations of the incident and the practices of qualifying persons to perform plastic fusions. Pursuant to the agreement, the company will provide $27 million of future benefits to customers (for which it has accrued a regulatory liability, see Note B) and will not recover from customers $126 million of costs for gas emergency response activities that it had previously incurred and expensed. Approximately eighty suits are pending against the company seeking generally unspecified damages and, in some cases, punitive damages, for wrongful death, personal injury, property damage and business interruption. The company has notified its insurers of the incident and believes that the policies in force at the time of the incident will cover the company’s costs, in excess of a required retention (the amount of which is not material), to satisfy any liability it may have for damages in connection with the incident. The company is unable to estimate the amount or range of its possible loss for damages related to the incident. At December 31, 2017, the company had not accrued a liability for damages related to the incident. Other Contingencies See “Other Regulatory Matters” in Note B and "Uncertain Tax Positions" in Note L. Guarantees Con Edison and its subsidiaries enter into various agreements providing financial or performance assurance primarily to third parties on behalf of their subsidiaries. Maximum amounts guaranteed by Con Edison totaled $2,073 million and $2,370 million at December 31, 2017 and 2016, respectively. A summary, by type and term, of Con Edison’s total guarantees at December 31, 2017 is as follows:
Con Edison Transmission – Con Edison has guaranteed payment by CET Electric of the contributions CET Electric agreed to make to New York Transco LLC (NY Transco). CET Electric acquired a 45.7 percent interest in NY Transco when it was formed in 2014. In May 2016, the transmission owners transferred certain projects to NY Transco, for which CET Electric made its required contributions. NY Transco has proposed other transmission projects in the New York Independent System Operator's competitive bidding process. These other projects are subject to certain authorizations from the NYSPSC, the FERC and, as applicable, other federal, state and local agencies. Guarantee amount shown is for the maximum possible required amount of CET Electric's contributions for these other projects as calculated based on the assumptions that the projects are completed at 175 percent of their estimated costs and NY Transco does not use any debt financing for the projects. Guarantee term shown is assumed as the selection of the projects and resulting timing of the contributions is not certain. Also included within the table above is a guarantee for $25 million from Con Edison on behalf of CET Gas in relation to a proposed gas transmission project in West Virginia and Virginia. See Note U. Energy Transactions — Con Edison guarantees payments on behalf of the Clean Energy Businesses in order to facilitate physical and financial transactions in electricity, gas, pipeline capacity, transportation, oil, renewable energy credits and energy services. To the extent that liabilities exist under the contracts subject to these guarantees, such liabilities are included in Con Edison’s consolidated balance sheet. Renewable Electric Production Projects – Con Edison, Con Edison Development and Con Edison Solutions guarantee payments on behalf of their wholly-owned subsidiaries associated with their investment in, or development for others of, solar and wind energy facilities. Other – Other guarantees include $70 million in guarantees provided by Con Edison to Travelers Insurance Company for indemnity agreements for surety bonds in connection with operation of solar energy facilities and energy service projects of Con Edison Development and Con Edison Solutions, respectively. Other guarantees also include Con Edison's guarantee (subject to a $53 million maximum amount) of certain obligations of Con Edison Solutions under the agreement pursuant to which it sold its retail electric supply business. See Note U. |
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- References No definition available.
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- Definition The entire disclosure for commitments and contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Electricity Purchase Agreements |
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| Regulated Operations [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Electricity Purchase Agreements | Regulatory Matters Rate Plans The Utilities provide service to New York customers according to the terms of tariffs approved by the NYSPSC. Tariffs for service to customers of Rockland Electric Company (RECO), O&R’s New Jersey regulated utility subsidiary, are approved by the New Jersey Board of Public Utilities (NJBPU). The tariffs include schedules of rates for service that limit the rates charged by the Utilities to amounts that recover from their customers costs approved by the regulator, including capital costs, of providing service to customers as defined by the tariff. The tariffs implement rate plans adopted by state utility regulators in rate orders issued at the conclusion of rate proceedings. Pursuant to the Utilities’ rate plans, there generally can be no change to the charges to customers during the respective terms of the rate plans other than specified adjustments provided for in the rate plans. The Utilities’ rate plans each cover specified periods, but rates determined pursuant to a plan generally continue in effect until a new rate plan is approved by the state utility regulator. Common provisions of the Utilities’ New York rate plans include: Recoverable energy costs that allow the Utilities to recover on a current basis the costs for the energy they supply with no mark-up to their full-service customers. Cost reconciliations that reconcile pension and other postretirement benefit costs, environmental remediation costs, property taxes, variable rate tax-exempt debt and certain other costs to amounts reflected in delivery rates for such costs. In addition, changes in the Utilities' costs not reflected in rates, in excess of certain amounts, resulting from changes in tax or other law, rule, regulation, order, or other requirement or interpretation are deferred as a regulatory asset or regulatory liability to be reflected in the Utilities' next rate plan or in a manner to be determined by the NYSPSC. See "Other Regulatory Matters," below. Also, the Utilities generally retain the right to petition for recovery or accounting deferral of extraordinary and material cost increases and provision is sometimes made for the utility to retain a share of cost reductions, for example, property tax refunds. Revenue decoupling mechanisms that reconcile actual energy delivery revenues to the authorized delivery revenues approved by the NYSPSC. The difference is accrued with interest for refund to, or recovery from customers, as applicable. Earnings sharing that require the Utilities to defer for customer benefit a portion of earnings over specified rates of return on common equity. There is no symmetric mechanism for earnings below specified rates of return on common equity. Negative revenue adjustments for failure to meet certain performance standards relating to service, reliability, safety and other matters. Positive revenue adjustments for achievement of performance standards related to achievement of clean energy goals, safety and other matters. Net utility plant reconciliations that require deferral as a regulatory liability of the revenue requirement impact of the amount, if any, by which actual average net utility plant balances are less than amounts reflected in rates. There is generally no symmetric mechanism if actual average net utility plant balances are more than amounts reflected in rates. Rate base, as reflected in the rate plans, is, in general, the sum of the Utilities’ net plant, working capital and certain regulatory assets less deferred taxes and certain regulatory liabilities. For each rate plan, the NYSPSC uses a forecast of the average rate base for each year that new rates would be in effect (“rate year”). Weighted average cost of capital is determined based on the authorized common equity ratio, return on common equity, cost of long-term debt and customer deposits reflected in each rate plan. For each rate plan, the revenues designed to provide the utility a return on invested capital for each rate year are determined by multiplying each utility rate base by its pre–tax weighted average cost of capital. The Utilities’ actual return on common equity will reflect their actual operations for each rate year, and may be more or less than the authorized return on equity reflected in their rate plans (and if more, may be subject to earnings sharing). The following tables contain a summary of the Utilities’ rate plans:
In January 2018, O&R filed a request with the NYSPSC for an increase in the rates it charges for electric service rendered in New York, effective January 1, 2019, of $20.3 million. The filing reflects a return on common equity of 9.75 percent and a common equity ratio of 48 percent. The filing proposes continuation of the provisions with respect to recovery from customers of the cost of purchased power, and the reconciliation of actual expenses allocable to the electric business to the amounts for such costs reflected in electric rates for storm costs, pension and other postretirement benefit costs, environmental remediation and property taxes.
In January 2018, O&R filed a request with the NYSPSC for an increase in the rates it charges for gas service rendered in New York, effective January 1, 2019, of $4.5 million. The filing reflects a return on common equity of 9.75 percent and a common equity ratio of 48 percent. The filing proposes continuation of the provisions with respect to recovery from customers of the cost of purchased gas, and the reconciliation of actual expenses allocable to the gas business to the amounts for such costs reflected in gas rates for pension and other postretirement benefit costs, environmental remediation and property taxes.
In November 2017, FERC approved a September 2017 settlement agreement among RECO, the New Jersey Division of Rate Counsel and the NJBPU that increases RECO's annual transmission revenue requirement from $11.8 million to $17.7 million, effective April 2017. The revenue requirement reflects a return on common equity of 10.0 percent. Other Regulatory Matters In August and November 2017, the NYSPSC issued orders in its proceeding investigating an April 21, 2017 Metropolitan Transportation Authority (MTA) subway power outage. The orders indicated that the investigation determined that the outage was caused by a failure of CECONY’s electricity supply to a subway station, which led to a loss of the subway signals, and that one of the secondary services to the MTA facility had been improperly rerouted and was not properly documented by the company. The orders also indicated that the loss of power to the subway station affected multiple subway lines and caused widespread delays across the subway system. Pursuant to the orders, the company is required to take certain actions, including inspecting, repairing and installing certain electrical equipment that serves the subway system, analyzing power supply and power quality events affecting the MTA’s signaling services, and filing monthly reports with the NYSPSC on all of the company's activities related to the subway system. In July 2017, the Chairman of the NYSPSC notified the company that the April 21, 2017 subway power outage incident will likely result in a prudence review of the reasonableness of CECONY's actions and conduct. The orders did not commence a prudence review. The company incurred costs related to this matter in 2017 of $65 million. Included in this amount is $15 million in capital and operating and maintenance costs reflected in the company's electric rate plan and $50 million deferred as a regulatory asset pursuant to the rate plan. The company, which plans to complete the required actions in 2018, expects to incur costs related to this matter in 2018 of $137 million. Included in this amount is $10 million in expected capital and operating and maintenance costs reflected in the rate plan and $127 million expected to be deferred as a regulatory asset pursuant to the rate plan. In December 2017, the NYSPSC issued an order initiating a proceeding to study the potential effects of the TCJA on the tax expenses and liabilities of New York State utilities and the regulatory treatment to preserve the resulting benefits for customers. In January 2018, the NJBPU issued an order initiating a proceeding to consider the TCJA. Upon enactment of the TCJA, CECONY, O&R and RECO re-measured their deferred tax assets and liabilities based upon the 21 percent corporate income tax rate under the TCJA. As a result, CECONY, O&R and RECO, decreased their net deferred tax liabilities by $4,781 million, $216 million and $45 million, respectively, decreased their regulatory asset for future income tax by $1,182 million, $51 million and $17 million, respectively, decreased their regulatory asset for revenue taxes by $86 million, $4 million and $0 million, respectively, and accrued regulatory liabilities for future income tax of $3,513 million, $161 million and $28 million, respectively. See Note L. In January 2018, the NYSPSC issued an order initiating a focused operations audit of the income tax accounting of certain utilities, including CECONY and O&R. See footnote (h) to the table under "CECONY – Electric," above. Regulatory Assets and Liabilities Regulatory assets and liabilities at December 31, 2017 and 2016 were comprised of the following items:
Unrecognized pension and other postretirement costs represent the net regulatory asset associated with the accounting rules for retirement benefits. See Note A. Revenue taxes represent the timing difference between taxes collected and paid by the Utilities to fund mass transportation. Deferred storm costs represent response and restoration costs, other than capital expenditures, in connection with Superstorm Sandy and other major storms that were deferred by the Utilities. Net electric deferrals represent the remaining unamortized balance of certain regulatory assets and liabilities of CECONY that were combined effective April 1, 2010 and are being amortized to income through March 31, 2018. Settlement of prudence proceeding represents the remaining amount to be credited to customers pursuant to a Joint Proposal, approved by the NYSPSC in April 2016, with respect to the prudence of certain CECONY expenditures and related matters. Settlement of gas proceedings represents the amount to be credited to customers pursuant to a settlement agreement approved by the NYSPSC in February 2017 related to CECONY’s practices of qualifying persons to perform plastic fusions on gas facilities and alleged violations of gas safety violations identified by the NYSPSC staff in its investigation of a March 2014 Manhattan explosion and fire (see Note H). The NYSPSC has authorized CECONY to accrue unbilled electric, gas and steam revenues. CECONY has deferred the net margin on the unbilled revenues for the future benefit of customers by recording a regulatory liability of $183 million and $145 million at December 31, 2017 and 2016, respectively, for the difference between the unbilled revenues and energy cost liabilities. Electricity Purchase Agreements The Utilities have electricity purchase agreements with non-utility generators and others for generating capacity. The Utilities recover their purchased power costs in accordance with provisions approved by the applicable state public utility regulators. See “Recoverable Energy Costs” in Note A. At December 31, 2017, the significant terms of the electricity purchase agreements with non-utility generators were as follows:
(a) A portion of this contract ended in 2017 and a portion ends in 2018. The Utilities also conducted auctions and have entered into various other electricity purchase agreements. Assuming performance by the parties to the electricity purchase agreements, the Utilities are obligated over the terms of the agreements to make capacity and other fixed payments. The future capacity and other fixed payments under the contracts are estimated to be as follows:
For energy delivered under most of the electricity purchase agreements, CECONY is obligated to pay variable prices. The company’s payments under the significant terms of the agreements for capacity, energy and other fixed payments in 2017, 2016 and 2015 were as follows:
(a) Contract term ended in 2017. (b) Contract term ended in 2016. (c) Contract term ended in 2015. |
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- Definition The entire disclosure for public utilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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Leases |
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| Leases [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Leases | Leases Con Edison’s subsidiaries lease electric transmission facilities, gas distribution facilities, land, office buildings and equipment. In accordance with the accounting rules for leases, these leases are classified as either capital leases or operating leases. Most of the operating leases provide the option to renew at the fair rental value for future periods. Generally, it is expected that leases will be renewed or replaced in the normal course of business. Capital leases: For ratemaking purposes capital leases are treated as operating leases; therefore, in accordance with the accounting rules for regulated operations, the amortization of the leased asset is based on the rental payments recovered from customers. The following assets under capital leases are included in the Companies’ consolidated balance sheets at December 31, 2017 and 2016:
The accumulated amortization of the capital leases for Con Edison and CECONY was $3 million and $2 million, respectively at December 31, 2017, and $3 million and $1 million, respectively at December 31, 2016. Operating leases: The future minimum lease commitments under the Companies’ operating lease agreements that are not cancellable by the Companies are as follows:
Substantially all of the amounts shown in the above table are estimated amounts payable under CECONY’s revocable consent agreement with New York City for the use of streets and public places for installation and operation of transformers and associated vaults and equipment. Under the agreement, payments by CECONY increase 2.18 percent annually and are subject to decrease if CECONY’s transformer installations decrease by ½ of 1 percent or more from the prior year. For information about changes to the accounting rules for leases, see Note T. |
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- References No definition available.
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- Definition The entire disclosure for lessee entity's leasing arrangements including, but not limited to, all of the following: (a.) The basis on which contingent rental payments are determined, (b.) The existence and terms of renewal or purchase options and escalation clauses, (c.) Restrictions imposed by lease agreements, such as those concerning dividends, additional debt, and further leasing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Goodwill and Other Intangible Assets |
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Dec. 31, 2017 | |
| Goodwill and Intangible Assets Disclosure [Abstract] | |
| Goodwill and Other Intangible Assets | Goodwill and Other Intangible Assets In 2017, Con Edison elected to perform the optional qualitative assessment for goodwill related to the O&R merger and the gas storage company, and the first step of the quantitative test for the residential solar company. In 2016 Con Edison performed the first step of the quantitative analysis for the goodwill related to the O&R merger, the gas storage company, and the residential solar company and deemed that the second step assessment was not required. In 2017 and 2016, Con Edison completed impairment tests for its goodwill of $406 million related to the O&R merger, and determined that it was not impaired. For the impairment test, $245 million and $161 million of goodwill were allocated to CECONY and O&R, respectively. In 2017 and 2016, Con Edison completed impairment tests for goodwill of $8 million related to a gas storage company acquired by CET Gas from Con Edison Development and determined that it was not impaired. In 2016, Con Edison completed impairment tests for goodwill of $15 million related to two energy services companies owned by the Clean Energy Businesses and determined that goodwill was impaired and, upon calculating the implied fair value of goodwill using fair values based primarily on discounted cash flows, recorded a corresponding impairment charge of $15 million ($12 million, net of tax). Additionally, in 2016, the Clean Energy Businesses acquired a residential solar company and recorded $14 million of goodwill as part of the preliminary purchase price allocation. In 2017, Con Edison determined that goodwill related to the residential solar company was not impaired. Estimates of future cash flows, projected growth rates, and discount rates inherent in the cash flow estimates for Con Edison subsidiaries other than the Utilities may vary significantly from actual results, which could result in a future impairment of goodwill. For information about changes to the accounting rules for goodwill, see Note T. Con Edison's other intangible assets consist primarily of power purchase agreements, which were identified as part of purchase price allocations associated with acquisitions made by Con Edison Development in 2016. At December 31, 2017 and 2016, intangible assets arising from power purchase agreements were $131 million and $119 million, net of accumulated amortization of $9 million and $1 million, respectively, and are being amortized over the life of each agreement. Excluding power purchase agreements, Con Edison’s other intangible assets were an immaterial amount and $5 million, net of accumulated amortization of $6 million and $5 million, at December 31, 2017 and 2016, respectively. CECONY’s other intangible assets were immaterial at December 31, 2017 and 2016. Con Edison recorded amortization expense related to its intangible assets of $9 million in 2017, $2 million in 2016 and an immaterial amount in 2015. Con Edison expects amortization expense to be $9 million per year over the next five years. |
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- References No definition available.
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- Definition The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Income Tax |
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| Income Tax Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Income Tax | Income Tax The components of income tax are as follows:
The tax effects of temporary differences, which gave rise to deferred tax assets and liabilities, are as follows:
The TCJA includes significant changes affecting the taxation of regulated public utilities, such as CECONY and O&R, and Con Edison’s other businesses. Substantially all of the provisions of the TCJA are effective for taxable years beginning after December 31, 2017. The TCJA reduces the corporate federal income tax rate from 35 percent to 21 percent. The specific provisions related to regulated public utilities in the TCJA generally allow for the continued deductibility of interest expense, do not allow for full expensing for tax purposes of certain property acquired after September 27, 2017, and continue certain rate normalization requirements for accelerated depreciation benefits. For other businesses, TCJA provides for full expensing of property acquired after September 27, 2017 and limits a deduction for interest expense to 30 percent of adjusted taxable income (which resembles earnings before interest, taxes, depreciation and amortization or “EBITDA”). In accordance with the accounting rules for income taxes (see “Federal Income Tax” in Note A), the tax effects of changes in tax laws are to be recognized in the period in which the law is enacted and deferred tax assets and liabilities are to be re-measured at the enacted tax rate expected to apply when temporary differences are to be realized or settled. For CECONY and O&R, in accordance with their New York rate plans and the accounting rules for regulated operations the change in deferred taxes was recorded as either an offset to a regulatory asset or a regulatory liability. See “Accounting Policies” in Note A and “Rate Plans” in Note B. For Con Edison’s other businesses, the change in deferred taxes was reflected as a decrease in income tax expense, which increased Con Edison's net income. Upon enactment of the TCJA, the Companies re-measured their deferred tax assets and liabilities based upon the TCJA’s 21 percent corporate federal income tax rate. As a result, Con Edison, decreased its net deferred tax liabilities by $5,312 million (including $4,781 million for CECONY), recognized $259 million in net income, decreased its regulatory asset for future income tax by $1,250 million (including $1,182 million for CECONY), decreased the regulatory asset for revenue taxes by $90 million (including $86 million for CECONY), and accrued a regulatory liability for future income tax of $3,713 million (including $3,513 million for CECONY). Since the Companies are in a net regulatory liability position with respect to these income tax matters, the Companies netted the regulatory asset for future income tax against the regulatory liability for future income tax. Under the rate normalization requirements continued by the TCJA, $2,684 million of the net regulatory liability (including $2,542 million for CECONY) related to certain accelerated tax depreciation benefits is to be amortized over the remaining lives of the related assets. The remainder of the net regulatory liability is to be refunded (or credited) to customers as determined by the NYSPSC or NJBPU, as applicable. See “Other Regulatory Matters” in Note B. The amount recognized in net income included $269 million for the Clean Energy Businesses, $11 million for Con Edison Transmission and $(21) million for the parent company. The re-measurement had no impact on the Companies’ cash flows for 2017. SEC Staff Accounting Bulletin 118 (SAB 118), issued when the TCJA was enacted, clarifies accounting for income taxes if information is not yet available or complete and provides for up to a one year period in which to complete the required analyses and accounting. SAB 118 describes three scenarios associated with a company’s status of accounting for income tax reform: (1) a company is complete with its accounting for certain effects of tax reform, (2) a company is able to determine a reasonable estimate for certain effects of tax reform and records that estimate as a provisional amount, or (3) a company is not able to determine a reasonable estimate and therefore continues to apply the accounting rules for income taxes, based on the provisions of the tax laws that were in effect immediately prior to the TCJA being enacted. The Companies have completed the required analysis and accounting for substantially all the effects of the TCJA’s enactment and have made a reasonable estimate as to the other effects, and have reflected the measurement and accounting of the effects in their 2017 consolidated financial statements. The items reflected as provisional amounts include tax depreciation and amortization and other book/tax differences. The Companies have accounted for these items based on its interpretation of the TCJA. Further interpretive guidance on the TCJA from the IRS, U.S. Treasury Department, or the Joint Committee on Taxation may require adjustments to the Companies’ accounting. In accordance with SAB 118, adjustments, if any, will be recorded in 2018. The Companies did not identify any effects of the TCJA for which they were not able to either complete the required analysis or make a reasonable estimate. Reconciliation of the difference between income tax expense and the amount computed by applying the prevailing statutory income tax rate to income before income taxes is as follows:
In 2017, Con Edison had a federal net operating loss of approximately $121 million, due primarily to bonus depreciation. Con Edison expects to carryback approximately $53 million of its 2017 net operating loss to 2007, which will result in recovery of $19 million of income tax. The remaining 2017 federal net operating loss of $68 million will be carried forward to future years and will not expire until 2037. General business tax credits that were generated in 2017 ($176 million) will be carried forward to future years. Con Edison has $658 million in general business tax credit (primarily renewable energy tax credits), which if unused will begin to expire in 2032. A deferred tax asset for these tax attribute carryforwards was recorded, and no valuation allowance has been provided, as it is more likely than not that the deferred tax asset will be realized. For New York State income tax purposes, Con Edison has a net operating loss carryforward available from 2017 of $137 million, primarily as a result of accelerated tax deductions on renewable energy projects. A deferred tax asset has been recognized for this New York State net operating loss that will not expire until 2037. A valuation allowance has not been provided; as it is more likely than not that the deferred tax asset will be realized. Con Edison recorded a full valuation allowance of $3 million in 2015 against its charitable contribution carryforward from 2011. Due to the expiration of this charitable contribution carryforward in 2016, Con Edison wrote off the deferred tax asset and corresponding valuation allowance. Charitable contributions carryforward of $5 million, $5 million and $4 million for 2015, 2016 and 2017, respectively, that will expire in 2020, 2021 and 2022, respectively, were recorded as a deferred tax asset and no valuation allowance has been provided, as it is more likely than not that the deferred tax asset will be realized. In addition, a $21 million valuation allowance for New York City net operating loss carryforward and a $12 million valuation allowance for state net operating losses carryforward has been provided; as it is not more likely than not that the deferred tax asset will be realized. The Protecting Americans from Tax Hikes Act of 2015 extended bonus depreciation for property acquired and placed in service during 2015 through 2019. The bonus depreciation percentage is 50 percent for property placed in service during 2015, 2016 and 2017 and phases down to 40 percent in 2018, and 30 percent in 2019. As a result of the extension of bonus depreciation to 2015, Con Edison, in February 2016, received a refund of 2015 estimated taxes paid in the amount of $160 million ($143 million for CECONY). The TCJA does not allow bonus depreciation for property acquired and placed into service by regulated public utilities after September 27, 2017, but provides for full expensing for Con Edison's other businesses. Uncertain Tax Positions Under the accounting rules for income taxes, the Companies are not permitted to recognize the tax benefit attributable to a tax position unless such position is more likely than not to be sustained upon examination by taxing authorities, including resolution of any related appeals and litigation processes, based solely on the technical merits of the position. A reconciliation of the beginning and ending amounts of unrecognized tax benefits for Con Edison and CECONY follows:
In 2017, Con Edison reached a settlement with New York State on tax years 2006 through 2009 and on two significant items through 2015 and reversed $30 million in uncertain tax positions. Of this amount, $6 million ($4 million, net of federal taxes) reduced Con Edison’s effective tax rate. The amount related to CECONY was $18 million ($12 million, net of federal taxes), all of which reduced CECONY’s unamortized state investment tax credits. Current and prior year additions in 2017 are for tax credits. As of December 31, 2017, Con Edison reasonably expects to resolve within the next twelve months approximately $8 million ($7 million, net of federal taxes) of various federal and state uncertainties due to the expected completion of ongoing tax examinations and expiration of statute of limitations, of which the entire amount, if recognized, would reduce Con Edison’s effective tax rate. The amount related to CECONY is approximately $4 million, of which the entire amount, if recognized, would reduce CECONY’s effective tax rate. The Companies recognize interest on liabilities for uncertain tax positions in interest expense and would recognize penalties, if any, in operating expenses in the Companies’ consolidated income statements. In 2017, 2016 and 2015, the Companies recognized an immaterial amount of interest and no penalties for uncertain tax positions in their consolidated income statements. At December 31, 2017 and 2016, the Companies reflected an immaterial amount of interest and no penalties in their consolidated balance sheets. At December 31, 2017, the total amount of unrecognized tax benefits that, if recognized, would reduce the Companies’ effective tax rate is $12 million ($11 million, net of federal taxes) with $5 million attributable to CECONY. Federal tax returns for 2012 through 2016 remain under examination, with tax refunds for tax years 2012 through 2015 waiting for approval by the Joint Committee on Taxation. State income tax returns remain open for examination in New York for tax years 2010 through 2016 and in New Jersey for tax years 2008 through 2016. |
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- References No definition available.
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- Definition The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Stock-Based Compensation |
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| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Stock-Based Compensation | Stock-Based Compensation The Companies may compensate employees and directors with, among other things, stock options, stock units, restricted stock units and contributions to the stock purchase plan. The Long Term Incentive Plan, which was approved by Con Edison’s shareholders in 2003 (2003 LTIP), and the Long Term Incentive Plan, which was approved by Con Edison’s shareholders in 2013 (2013 LTIP), are collectively referred to herein as the LTIP. The LTIP provides for, among other things, awards to employees of restricted stock units and stock options and, to Con Edison’s non-employee directors, stock units. Existing awards under the 2003 LTIP continue in effect, however no new awards may be issued under the 2003 LTIP. The 2013 LTIP provides for awards for up to five million shares of common stock. Shares of Con Edison common stock used to satisfy the Companies’ obligations with respect to stock-based compensation may be new (authorized, but unissued) shares, treasury shares or shares purchased in the open market. The shares used during the year ended December 31, 2017 were new shares. The Companies intend to use new shares to fulfill their stock-based compensation obligations for 2018. The Companies recognized stock-based compensation expense using a fair value measurement method. The following table summarizes stock-based compensation expense recognized by the Companies in the years ended December 31, 2017, 2016 and 2015:
Stock Options The Companies last granted stock options in 2006. The stock options generally vested over a three-year period and had a term of 10 years. Options were granted at an exercise price equal to the fair market value of a common share when the option was granted. The Companies generally recognized compensation expense (based on the fair value of stock option awards) over the vesting period. At December 31, 2017 and 2016, there were no outstanding options. The aggregate intrinsic value of options exercised in 2016 for Con Edison and CECONY was $2 million. Aggregate intrinsic value represents the changes in the fair value of all outstanding options from their grant dates to December 31, 2016. Cash received by Con Edison for payment of the exercise price for Con Edison and CECONY options in 2016 was $3 million. No options were exercised in 2017. The income tax benefit Con Edison realized from stock options exercised in the years ended December 31, 2016 and 2015 was $1 million. Restricted Stock and Stock Units Restricted stock and stock unit awards under the LTIP have been made as follows: (i) awards that provide for adjustment of the number of units (performance-restricted stock units or Performance RSUs) to certain officers and employees; (ii) time-based awards to certain employees; and (iii) awards to non-employee directors. Restricted stock and stock units awarded represents the right to receive, upon vesting, shares of Con Edison common stock, or, except for units awarded under the directors’ plan, the cash value of shares or a combination thereof. The number of units in each annual Performance RSU award is subject to adjustment as follows: (i) 50 percent of the units awarded will be multiplied by a factor that may range from 0 to 200 percent, based on Con Edison’s total shareholder return relative to a specified peer group during a specified performance period (the TSR portion); and (ii) 50 percent of the units awarded will be multiplied by factors that may range from 0 to 200 percent, based on determinations made in connection with the Companies’ annual incentive plans or, for certain executive officers, actual performance as compared to certain performance measures during a specified performance period (the non-TSR portion). Performance RSU awards generally vest upon completion of the performance period. Performance against the established targets is recomputed each reporting period as of the earlier of the reporting date and the vesting date. The TSR portion applies a Monte Carlo simulation model, and the non-TSR portion is the product of the market price at the end of the period and the average non-TSR determination over the vesting period. Performance RSUs are “liability awards” because each Performance RSU represents the right to receive, upon vesting, one share of Con Edison common stock, the cash value of a share or a combination thereof. As such, changes in the fair value of the Performance RSUs are reflected in net income. The assumptions used to calculate the fair value of the awards were as follows:
A summary of changes in the status of the Performance RSUs’ TSR and non-TSR portions during the year ended December 31, 2017 is as follows:
The total expense to be recognized by Con Edison in future periods for unvested Performance RSUs outstanding at December 31, 2017 is $38 million, including $31 million for CECONY, and is expected to be recognized over a weighted average period of one year for both Con Edison and CECONY. In accordance with the accounting rules for stock compensation, for time-based awards, the Companies are accruing a liability and recognizing compensation expense based on the market value of a common share throughout the vesting period. The vesting period for awards is three years and is based on the employee’s continuous service to Con Edison. Prior to vesting, the awards are subject to forfeiture in whole or in part under certain circumstances. The awards are “liability awards” because each restricted stock unit represents the right to receive, upon vesting, one share of Con Edison common stock, the cash value of a share or a combination thereof. As such, prior to vesting, changes in the fair value of the units are reflected in net income. A summary of changes in the status of time-based awards during the year ended December 31, 2017 is as follows:
The total expense to be recognized by Con Edison in future periods for unvested time-based awards outstanding at December 31, 2017 for Con Edison and CECONY was $2 million and is expected to be recognized over a weighted average period of one year. Under the LTIP, each non-employee director receives stock units, which are deferred until the director’s separation from service or another date specified by the director. Each director may also elect to defer all or a portion of their cash compensation into additional stock units, which are deferred until the director’s termination of service or another date specified by the director. Non-employee directors’ stock units issued under the LTIP are considered “equity awards,” because they may only be settled in shares. Directors immediately vest in units issued to them. The fair value of the units is determined using the closing price of Con Edison’s common stock on the business day immediately preceding the date of issue. In the year ended December 31, 2017, approximately 28,100 units were issued at a weighted average grant date price of $81.15. Stock Purchase Plan The Stock Purchase Plan, which was approved by shareholders in 2004 and 2014, provides for the Companies to contribute up to $1 for each $9 invested by their directors, officers or employees to purchase Con Edison common stock under the plan. Eligible participants may invest up to $25,000 during any calendar year (subject to an additional limitation for officers and employees of not more than 20 percent of their pay). Dividends paid on shares held under the plan are reinvested in additional shares unless otherwise directed by the participant. Participants in the plan immediately vest in shares purchased by them under the plan. The fair value of the shares of Con Edison common stock purchased under the plan was calculated using the average of the high and low composite sale prices at which shares were traded at the New York Stock Exchange on the trading day immediately preceding such purchase dates. During 2017, 2016 and 2015, 719,125, 720,268 and 761,784 shares were purchased under the Stock Purchase Plan at a weighted average price of $79.57, $72.67 and $62.75 per share, respectively. |
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- Definition The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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Financial Information by Business Segment |
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| Segment Reporting [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Financial Information by Business Segment | Financial Information by Business Segment The business segments of each of the Companies, which are its operating segments, were determined based on management’s reporting and decision-making requirements in accordance with the accounting rules for segment reporting. Con Edison’s principal business segments are CECONY’s regulated utility activities, O&R’s regulated utility activities, the Clean Energy Businesses and Con Edison Transmission. CECONY’s principal business segments are its regulated electric, gas and steam utility activities. Con Edison Transmission, which had begun investing in electric transmission and gas pipeline and storage assets (see Note U), was added in June 2016 as a separate reportable segment based on management’s reporting and decision-making, including performance evaluation and resource allocation. For comparison purposes, the previously reported financial information by business segments was reclassified to reflect the current business segment presentation. All revenues of these business segments are from customers located in the United States of America. Also, all assets of the business segments are located in the United States of America. The accounting policies of the segments are the same as those described in Note A. Common services shared by the business segments are assigned directly or allocated based on various cost factors, depending on the nature of the service provided. The financial data for the business segments are as follows:
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- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Derivative Instruments and Hedging Activities |
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| Derivative Instruments and Hedging Activities Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Derivative Instruments and Hedging Activities | Derivative Instruments and Hedging Activities Commodity Derivatives Con Edison’s subsidiaries hedge market price fluctuations associated with physical purchases and sales of electricity, natural gas, steam and, to a lesser extent, refined fuels by using derivative instruments including futures, forwards, basis swaps, options, transmission congestion contracts and financial transmission rights contracts. Derivatives are recognized on the consolidated balance sheet at fair value (see Note P), unless an exception is available under the accounting rules for derivatives and hedging. Qualifying derivative contracts that have been designated as normal purchases or normal sales contracts are not reported at fair value under the accounting rules. The fair values of the Companies’ commodity derivatives including the offsetting of assets and liabilities on the consolidated balance sheet at December 31, 2017 and 2016 were:
The Utilities generally recover their prudently incurred fuel, purchased power and gas costs, including hedging gains and losses, in accordance with rate provisions approved by the applicable state utility regulators. See "Recoverable Energy Costs" in Note A. In accordance with the accounting rules for regulated operations, the Utilities record a regulatory asset or liability to defer recognition of unrealized gains and losses on their electric and gas derivatives. As gains and losses are realized in future periods, they will be recognized as purchased power, gas and fuel costs in the Companies’ consolidated income statements. The Clean Energy Businesses record realized and unrealized gains and losses on their derivative contracts in purchased power, gas purchased for resale and non-utility revenue in the reporting period in which they occur. Management believes that these derivative instruments represent economic hedges that mitigate exposure to fluctuations in commodity prices. The following table presents the realized and unrealized gains or losses on commodity derivatives that have been deferred or recognized in earnings for the years ended December 31, 2017 and 2016:
The following table presents the hedged volume of Con Edison’s and CECONY’s derivative transactions at December 31, 2017:
The Companies are exposed to credit risk related to transactions entered into primarily for the various energy supply and hedging activities by the Utilities and the Clean Energy Businesses. Credit risk relates to the loss that may result from a counterparty’s nonperformance. The Companies use credit policies to manage this risk, including an established credit approval process, monitoring of counterparty limits, netting provisions within agreements, collateral or prepayment arrangements, credit insurance and credit default swaps. The Companies measure credit risk exposure as the replacement cost for open energy commodity and derivative positions plus amounts owed from counterparties for settled transactions. The replacement cost of open positions represents unrealized gains, net of any unrealized losses where the Companies have a legally enforceable right to offset. At December 31, 2017, Con Edison and CECONY had $103 million and $28 million of credit exposure in connection with energy supply and hedging activities, net of collateral, respectively. Con Edison’s net credit exposure consisted of $39 million with investment-grade counterparties, $29 million with independent system operators, $22 million with commodity exchange brokers, and $13 million with non-investment grade/non-rated counterparties. CECONY’s net credit exposure consisted of $17 million with investment-grade counterparties and $11 million with commodity exchange brokers. The collateral requirements associated with, and settlement of, derivative transactions are included in net cash flows from operating activities in the Companies’ consolidated statement of cash flows. Most derivative instrument contracts contain provisions that may require a party to provide collateral on its derivative instruments that are in a net liability position. The amount of collateral to be provided will depend on the fair value of the derivative instruments and the party’s credit ratings. The following table presents the aggregate fair value of the Companies’ derivative instruments with credit-risk-related contingent features that are in a net liability position, the collateral posted for such positions and the additional collateral that would have been required to be posted had the lowest applicable credit rating been reduced one level and to below investment grade at December 31, 2017:
Interest Rate Swap In December 2016, the Clean Energy Businesses acquired Coram Wind which holds an interest rate swap that terminates in June 2024, pursuant to which it pays a fixed-rate of 2.0855 percent and receives a LIBOR-based variable rate. The fair value of this interest rate swap was immaterial as of December 31, 2017 and a liability of $1 million as of December 31, 2016 on Con Edison’s consolidated balance sheet. |
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- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements |
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| Fair Value Disclosures [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Fair Value Measurements | Fair Value Measurements The accounting rules for fair value measurements and disclosures define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated, or generally unobservable firm inputs. The Companies often make certain assumptions that market participants would use in pricing the asset or liability, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. The Companies use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. The accounting rules for fair value measurements and disclosures established a fair value hierarchy, which prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The rules require that assets and liabilities be classified in their entirety based on the level of input that is significant to the fair value measurement. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and their placement within the fair value hierarchy. The Companies classify fair value balances based on the fair value hierarchy defined by the accounting rules for fair value measurements and disclosures as follows:
Assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2017 and 2016 are summarized below.
The employees in the Companies’ risk management group develop and maintain the Companies’ valuation policies and procedures for, and verify pricing and fair value valuation of, commodity derivatives. Under the Companies’ policies and procedures, multiple independent sources of information are obtained for forward price curves used to value commodity derivatives. Fair value and changes in fair value of commodity derivatives are reported on a monthly basis to the Companies’ risk committees, comprised of officers and employees of the Companies that oversee energy hedging at the Utilities and the Clean Energy Businesses. The risk management group reports to the Companies’ Vice President and Treasurer.
The table listed below provides a reconciliation of the beginning and ending net balances for assets and liabilities measured at fair value for the years ended December 31, 2017 and 2016 and classified as Level 3 in the fair value hierarchy:
For the Utilities, realized gains and losses on Level 3 commodity derivative assets and liabilities are reported as part of purchased power, gas and fuel costs. The Utilities generally recover these costs in accordance with rate provisions approved by the applicable state public utilities regulators. See Note A. Unrealized gains and losses for commodity derivatives are generally deferred on the consolidated balance sheet in accordance with the accounting rules for regulated operations. For the Clean Energy Businesses, realized and unrealized gains and losses on Level 3 commodity derivative assets and liabilities are reported in non-utility revenues ($2 million gain and immaterial) and purchased power costs (immaterial and $6 million loss) on the consolidated income statement for the years ended December 31, 2017 and 2016, respectively. The change in fair value relating to Level 3 commodity derivative assets and liabilities held at December 31, 2017 and 2016 is included in non-utility revenues ($2 million gain and immaterial) and purchased power costs (immaterial and $1 million loss) on the consolidated income statement for the years ended December 31, 2017 and 2016, respectively. |
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- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure of the fair value measurement of assets and liabilities, which includes financial instruments measured at fair value that are classified in shareholders' equity, which may be measured on a recurring or nonrecurring basis. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Variable Interest Entities |
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| Equity Method Investments and Joint Ventures [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Variable Interest Entities | Variable Interest Entities The accounting rules for consolidation address the consolidation of a variable interest entity (VIE) by a business enterprise that is the primary beneficiary. A VIE is an entity that does not have a sufficient equity investment at risk to permit it to finance its activities without additional subordinated financial support, or whose equity investors lack the characteristics of a controlling financial interest. The primary beneficiary is the business enterprise that has the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and either absorbs a significant amount of the VIE’s losses or has the right to receive benefits that could be significant to the VIE. The Companies enter into arrangements including leases, partnerships and electricity purchase agreements, with various entities. As a result of these arrangements, the Companies retain or may retain a variable interest in these entities. CECONY CECONY has an ongoing long-term electricity purchase agreement with Brooklyn Navy Yard Cogeneration Partners, LP, a potential VIE. In April 2017, CECONY's long-term electricity purchase agreement with Cogen Technologies Linden Venture, LP, another potential VIE, expired. In 2017, requests were made of these counterparties for information necessary to determine whether the entity was a VIE and whether CECONY is the primary beneficiary; however, the information was not made available. See Note I for information on these electricity purchase agreements, the payments pursuant to which constitute CECONY's maximum exposure to loss with respect to the potential VIEs. Con Edison Development Con Edison has a variable interest in OCI Solar San Antonio 4 LLC (Texas Solar 4), which is a consolidated entity in which Con Edison Development has an 80 percent membership interest. Con Edison is the primary beneficiary since the power to direct the activities that most significantly impact the economics of Texas Solar 4 is held by Con Edison Development. Texas Solar 4 owns a project company that developed a 40 MW (AC) solar electric production project in Texas. Electricity generated by the project is sold to the City of San Antonio pursuant to a long-term power purchase agreement. At December 31, 2017 and 2016, Con Edison’s consolidated balance sheet includes $26 million and $54 million in net assets (as detailed in the table below) respectively and the noncontrolling interest of the third party of $7 million related to Texas Solar 4. Earnings for the years ended December 31, 2017 and 2016 were immaterial.
The following table summarizes the VIEs in which Con Edison Development has entered into as of December 31, 2017:
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- References No definition available.
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| X | ||||||||||
- Definition The entire disclosure for a variable interest entity (VIE), including but not limited to, judgments and assumptions in determining whether to consolidate and in identifying the primary beneficiary, gain (loss) recognized on the initial consolidation of the VIE, terms of arrangements, amounts and classification of the VIE's assets and liabilities, and the entity's maximum exposure to loss. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Asset Retirement Obligations |
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Dec. 31, 2017 | |
| Asset Retirement Obligation Disclosure [Abstract] | |
| Asset Retirement Obligations | Asset Retirement Obligations The Companies recognize a liability at fair value for legal obligations associated with the retirement of long-lived assets in the period in which they are incurred, or when sufficient information becomes available to reasonably estimate the fair value of such legal obligations. When the liability is initially recorded, asset retirement costs are capitalized by increasing the carrying amount of the related asset. The liability is accreted to its present value each period and the capitalized cost is depreciated over the useful life of the related asset. The fair value of the asset retirement obligation liability is measured using expected future cash flows discounted at credit-adjusted risk-free rates, historical information, and where available, quoted prices from outside contractors. The Companies evaluate these assumptions underlying the asset retirement obligation liability on an annual basis or as frequently as needed. The Companies recorded asset retirement obligations associated with the removal of asbestos and asbestos-containing material in their buildings (other than the structures enclosing generating stations and substations), electric equipment and steam and gas distribution systems. The Companies also recorded asset retirement obligations relating to gas and oil pipelines abandoned in place and municipal infrastructure support. The Companies did not record an asset retirement obligation for the removal of asbestos associated with the structures enclosing generating stations and substations. For these building structures, the Companies were unable to reasonably estimate their asset retirement obligations because the Companies were unable to estimate the undiscounted retirement costs or the retirement dates and settlement dates. The amount of the undiscounted retirement costs could vary considerably depending on the disposition method for the building structures, and the method has not been determined. The Companies anticipate continuing to use these building structures in their businesses for an indefinite period, and so the retirement dates and settlement dates are not determinable. Con Edison recorded asset retirement obligations for the removal of the Clean Energy Businesses’ solar and wind equipment related to projects located on property that is not owned by them and the term of the arrangement is finite including any renewal options. Con Edison did not record asset retirement obligations for the Clean Energy Businesses’ projects that are located on property that is owned by them because they expect that the equipment will continue to generate electricity at these facilities long past the manufacturer’s warranty at minimal operating expense. Therefore, Con Edison was unable to reasonably estimate the retirement date of this equipment. The Utilities include in depreciation rates the estimated removal costs, less salvage, for utility plant assets. The amounts related to removal costs that are associated with asset retirement obligations are classified as an asset retirement liability. Pursuant to accounting rules for regulated operations, future removal costs that do not represent legal asset retirement obligations are recorded as regulatory liabilities. Accretion and depreciation expenses related to removal costs that represent legal asset retirement obligations are applied against the Companies’ regulatory liabilities. Asset retirement costs that are recoverable from customers are recorded as regulatory liabilities to reflect the timing difference between costs recovered through the rate-making process and recognition of costs. At December 31, 2017, the liabilities for asset retirement obligations of Con Edison and CECONY were $314 million and $287 million, respectively. At December 31, 2016, the liabilities for asset retirement obligations of Con Edison and CECONY were $246 million and $227 million, respectively. The change in liabilities at December 31, 2017 was due to changes in estimated cash flows of $98 million and $91 million for Con Edison and CECONY, respectively, and accretion expense of $10 million and $9 million for Con Edison and CECONY, respectively. The changes were offset by liabilities settled of $40 million for both Con Edison and CECONY. Con Edison and CECONY also recorded reductions of $36 million and $37 million during the years ended December 31, 2017 and 2016, respectively, to the regulatory liability associated with cost of removal to reflect depreciation and interest expense. |
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- References No definition available.
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- Definition The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Related Party Transactions |
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| Related Party Transactions [Abstract] | |||||||||||||||||||||||||
| Related Party Transactions | Related Party Transactions CECONY provides administrative and other services to, and receives such services from, Con Edison and its other subsidiaries pursuant to cost allocation procedures approved by the NYSPSC. The costs of administrative and other services provided by CECONY to, and received by it from, Con Edison and its other subsidiaries for the years ended December 31, 2017, 2016 and 2015 were as follows:
In addition, CECONY and O&R have joint gas supply arrangements, in connection with which CECONY sold to O&R $66 million, $47 million and $54 million of natural gas for the years ended December 31, 2017, 2016 and 2015, respectively. These amounts are net of the effect of related hedging transactions. The Utilities perform work and incur expenses on behalf of NY Transco, a company in which CET Electric has a 45.7 percent equity interest. The Utilities bill NY Transco for such work and expenses in accordance with established policies. For the year ended December 31, 2017 and 2016, the amounts billed by the Utilities to NY Transco were immaterial. In May 2016, CECONY transferred certain electric transmission projects to NY Transco. See Note U. CECONY has storage and wheeling service contracts with Stagecoach Gas Services LLC (Stagecoach), a joint venture formed by a subsidiary of CET Gas and a subsidiary of Crestwood Equity Partners LP (Crestwood). In addition, CECONY is the replacement shipper on one of Crestwood’s firm transportation agreements with Tennessee Gas Pipeline Company LLC. From the inception of the joint venture in June 2016 through December 31, 2017, the amount of storage and wheeling services received by CECONY from Stagecoach was $49 million. In addition, the Clean Energy Businesses entered into two electricity sales agreements with Stagecoach under which the amounts received in 2017 and 2016 were immaterial. CECONY has a 20-year transportation contract with Mountain Valley Pipeline, LLC (MVP) for 250,000 dekatherms per day of capacity. CET Gas holds a 12.5 percent equity interest in MVP. In October 2017, the Environmental Defense Fund and the Natural Resource Defense Council requested the NYSPSC to prohibit CECONY from recovering costs under its MVP contract. For the year ended December 31, 2017, CECONY incurred no costs under the contract. CECONY had a financial electric capacity contract with Con Edison Energy for the period May 2016 through April 2017. For the years ended December 31, 2017 and 2016, Con Edison Energy's realized gains under this contract were $3 million and immaterial, respectively. FERC has authorized CECONY through 2019 to lend funds to O&R from time to time, for periods of not more than 12 months, in amounts not to exceed $250 million outstanding at any time, at prevailing market rates. There were no outstanding loans to O&R at December 31, 2017 and 2016. |
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- References No definition available.
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- Definition The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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New Financial Accounting Standards |
12 Months Ended |
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Dec. 31, 2017 | |
| Accounting Changes and Error Corrections [Abstract] | |
| New Financial Accounting Standards | New Financial Accounting Standards In January 2018, the Companies adopted Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” including the amendments thereto, (the New Standard) using the modified retrospective approach the New Standard permitted. The New Standard supersedes the revenue recognition requirements within Accounting Standards Codification Topic 605, “Revenue Recognition,” and most industry-specific guidance (the Superseded Standard). The purpose of the New Standard is to create a consistent framework for revenue recognition. The New Standard clarifies how to measure and recognize revenue arising from customer contracts to depict the transfer of goods or services in an amount that reflects the consideration the entity expects to receive. The New Standard also clarifies key areas including principal/agent considerations, performance obligations, licensing, sales taxes, noncash consideration, and contracts. The majority of Con Edison’s’ revenues and substantially all of CECONY’s revenues are derived from the provision of electric, gas, and steam service to customers pursuant to the terms of tariffs approved by the NYSPSC or NJBPU. For such service, the Companies expect that the revenue from contracts with customers for a period that will be recorded under the New Standard will be equivalent to the revenue for the period that would have been recorded under the Superseded Standard. Most of Con Edison’s other revenues are derived from the Clean Energy Businesses’ sale of energy-related products and services, operation of renewable and energy infrastructure projects, and sale of renewable energy credits. For such businesses, Con Edison expects that the revenue from contracts with customers for a period that will be recorded under the New Standard will not be materially different from the revenue for the period that would have been recorded under the Superseded Standard. Under the modified retrospective method of adoption, prior year reported results are not restated and a cumulative-effect adjustment, if applicable, is recorded to retained earnings at January 1, 2018. As of January 1, 2018, the cumulative-effect adjustment was not material to the Companies. The Companies also plan to use certain practical expedients including applying this guidance to open contracts at the date of adoption and recognizing revenues for certain contracts under the invoice practical expedient. Such expedients allow revenue recognition to be consistent with invoiced amounts (including estimated billings) provided certain criteria are met, including consideration of whether the invoiced amounts reasonably represent the value provided to customers. The adoption of the New Standard will not have a material impact on the Companies’ financial statements, results of operations, and liquidity, including the presentation of revenues in their consolidated income statements. The adoption of the New Standard will not require a change in the Companies’ internal control over financial reporting that is reasonably likely to materially affect their internal control over financial reporting. In February 2016, the FASB issued amendments on financial reporting of leasing transactions through ASU No. 2016-02, “Leases (Topic 842)." The amendments require lessees to recognize assets and liabilities on the balance sheet and disclose key information about leasing arrangements. Lessees will need to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). Lessor accounting is similar to the current model, but updated to align with certain changes to the lessee model. For income statement purposes, the pattern of expense recognition will depend on whether transactions are designated as operating leases or finance leases. In January 2018, the FASB issued amendments on the lease standard’s application to land easements through ASU No. 2018-01, “Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842.” The amendments allow an entity to not evaluate under Topic 842 land easements that exist or expired before the entity’s adoption of Topic 842 and that were not previously accounted for as leases under the current lease standard. The amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The amendments must be adopted using a modified retrospective transition and provide for certain practical expedients. Based on the existing portfolio of leases at implementation, for leases currently classified as operating leases, the Companies expect to recognize on the statements of financial position right-of-use assets and lease liabilities. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ results of operations and liquidity. In January 2017, the FASB issued amendments to the guidance for Business Combinations through ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” The amendments in this update clarify the definition of a business and provide guidance on evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In January 2017, the FASB issued amendments to the guidance for the subsequent measurement of goodwill through ASU 2017-04, “Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The amendments in this update simplify goodwill impairment testing by eliminating Step 2 of the goodwill impairment test wherein an entity has to compute the implied fair value of goodwill by performing procedures to determine the fair value of its assets and liabilities. Under the new guidance, an entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value up to the total amount of goodwill allocated to that reporting unit. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In February 2017, the FASB issued amendments to the guidance for other income through ASU 2017-05, “Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets.” The amendments in this update clarify the scope of assets within Subtopic 610-20 and add guidance for partial sales of nonfinancial assets. The amendments are effective upon the adoption of ASU 2014-09, and therefore will be effective for reporting periods beginning after December 15, 2017. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2017, the FASB issued amendments to the guidance for retirement benefits through ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” The amendments in this update modify the presentation of net benefit cost, where the service component must be disaggregated from the other components of net benefit cost and be presented in the same line item as current employee compensation costs. The remaining components of the net benefit cost should be presented outside of income from operations. Additionally, the update allows only the service cost component to be eligible for capitalization. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. The guidance allows a practical expedient that permits the use of amounts disclosed in prior-period financial statements as appropriate estimates when applying the presentation requirements retrospectively. The Companies have elected to use the practical expedient under ASU 2017-07. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2017, the FASB issued amendments to the guidance for debt securities through ASU 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” The amendments in this update shorten the amortization period for certain callable debt securities held at a premium. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. For public entities, the amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In May 2017, the FASB issued amendments to the guidance for stock compensation through ASU 2017-09, “Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting.” The amendments in this update specify that changes to value, vesting conditions, or classification of an existing share-based payment award require application of modification accounting in Topic 718. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017.The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In August 2017, the FASB issued amendments to the guidance for derivatives and hedging through ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities.” The amendments in this update provide greater clarification on hedge accounting for risk components, presentation and disclosure of hedging instruments, and overall targeted improvements to simplify hedge accounting. For public entities, the amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ financial position, results of operations and liquidity. In February 2018, the FASB issued amendments to the guidance for reporting comprehensive income through ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” The amendments allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the TCJA. For public entities, the amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ financial position, results of operations and liquidity. |
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- References No definition available.
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- Definition The entire disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Acquisitions, Investments and Dispositions |
12 Months Ended |
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Dec. 31, 2017 | |
| Business Combinations [Abstract] | |
| Acquisitions, Investments and Dispositions | Acquisitions, Investments and Dispositions Acquisitions and Investments Texas Solar 7 In January 2016, Con Edison Development acquired a 100 percent equity interest in a company that is the owner of a 106 MW (AC) solar electric production project in Texas (Texas Solar 7) for $227 million, as to which $218 million was recorded as non-utility construction work in progress and the remaining $9 million was recorded as other receivables. The project commenced commercial operation in the third quarter of 2016. The project has been financed, in part, by debt secured by the project. Electricity generated by this project is to be purchased by the City of San Antonio pursuant to a long-term power purchase agreement. At December 31, 2017 and 2016, net assets of the project were approximately $137 million and $127 million, respectively, (including $41 million for an intangible asset pertaining to the value of the power purchase agreement). Con Edison's equity interest in Texas Solar 7 is consolidated in the financial statements. Mountain Valley Pipeline In January 2016, CET Gas acquired a 12.5 percent equity interest in MVP, a company developing a proposed gas transmission project in West Virginia and Virginia. The company's initial contribution to MVP was $18 million. At December 31, 2017 and 2016, CET Gas' investment in MVP was $98 million and $48 million, respectively. MVP has indicated that the project has an estimated total cost of $3,000 million to $3,500 million and is targeted to be fully in-service during the fourth quarter of 2018. Con Edison is accounting for its equity interest in MVP as an equity method investment. NY Transco In May 2016, CECONY transferred certain electric transmission projects to NY Transco, a company in which CET Electric has a 45.7 percent equity interest, for a purchase price of $122 million and an $8 million payment for associated easement rights. At December 31, 2017 and 2016, CET Electric's investment in NY Transco was $53 million and $51 million, respectively. Con Edison is accounting for its equity interest in NY Transco as an equity method investment. Stagecoach Gas Services In April 2016, a CET Gas subsidiary agreed with a subsidiary of Crestwood to form a joint venture to own, operate and further develop existing gas pipeline and storage businesses located in northern Pennsylvania and southern New York. The transaction was substantially completed in June 2016, and the remainder was completed in November 2016. Crestwood contributed businesses to a new entity, Stagecoach, and the CET Gas subsidiary contributed $974 million for a 50 percent equity interest in Stagecoach. At December 31, 2017 and 2016, CET Gas' investment in Stagecoach was $971 million and $992 million, respectively. Con Edison is accounting for its equity interest in Stagecoach as an equity method investment. Pilesgrove In June 2016, Con Edison Development recorded an $8 million ($5 million, net of taxes) impairment charge on its 50 percent equity interest in Pilesgrove Solar, LLC (Pilesgrove), which owns an 18 MW (AC) solar electric production project in New Jersey. In August 2016, Con Edison Development acquired the remaining 50 percent equity interest in Pilesgrove for a purchase price of approximately $16 million and recorded a bargain purchase gain of $8 million ($5 million, net of taxes); $45 million was recorded as non-utility property and the remaining $3 million was recorded as current assets. The impairment charge and bargain purchase gain are included in Investment and other income on Con Edison’s consolidated income statement. At December 31, 2017 and 2016, net assets of the project were approximately $45 million. Con Edison's equity interest in Pilesgrove is consolidated in the financial statements. Panoche Valley In October 2016, Con Edison Development, which owned a 50 percent equity interest, acquired the remaining 50 percent equity interest in Panoche Holdings, LLC (Panoche), which is developing a 240 MW (AC) solar electric production project in California, for cash consideration of $28 million and the release of Panoche from its obligation under a $242 million note payable to Con Edison Development. At the time of acquisition, $290 million was recorded as non-utility construction work in process, $22 million was recorded as other assets and $14 million was recorded as current liabilities. A part of the project commenced commercial operation in December 2017. At December 31, 2017 and 2016, net assets of the project were approximately $435 million and $388 million, respectively. Con Edison's equity interest in Panoche is consolidated in the financial statements. Coram Wind In December 2016, Con Edison Development acquired a 100 percent equity interest in Coram California Development, LP (Coram), which owns a 102 MW (AC) wind electric production project in California for $97 million, as to which $191 million was recorded as non-utility property, $78 million was recorded as an intangible asset, $8 million of restricted cash was recorded as other current assets, and $180 million was recorded as long term debt. In December 2017, an increase of $22 million was recorded to the intangible asset and a corresponding decrease was recorded to non-utility property. The intangible asset pertains to the value of the project's power purchase agreement, relative to current market rates, and is being amortized over the life of the agreement. The project commenced commercial operation in March 2012. At December 31, 2017 and 2016, net assets of the project were approximately $87 million and $96 million, respectively. Con Edison's equity interest in Coram is consolidated in the financial statements. Dispositions Pike County Light & Power Company (Pike) In October 2015, O&R entered into an agreement to sell Pike to Corning Natural Gas Holding Corporation (Corning). In August 2016, the sale was completed. O&R received cash consideration of $15 million for the sale. O&R has agreed to provide transition services to Corning for operations and customer support for a period of up to 18 months subsequent to the sale. In addition, O&R will continue to purchase and sell to Pike electric and gas commodity for three years. Pike has an option to extend the commodity procurement service for up to an additional three years. At September 30, 2015, O&R recorded an impairment charge of $5 million ($3 million, net of taxes), representing the difference between the carrying amount of Pike’s assets and the estimated sales proceeds. Con Edison Solutions' Retail Electric Supply Business In July 2016, Con Edison Solutions entered into an agreement to sell the assets of its retail electric supply business (including retail contracts, related derivative instruments, information systems, and accounts receivable) to a subsidiary of Exelon Corporation (Exelon). In September 2016, the sale was completed for cash consideration of $235 million, subject to working capital adjustments. The sale resulted in a gain of $104 million ($56 million, net of taxes), inclusive of a $65 million ($42 million, net of taxes) gain on derivative instruments. The tax effect of the sale included $16 million ($10 million, net of federal tax) of state taxes related to a change in the apportionment of state income taxes. Con Edison Solutions provided transition services to the Exelon subsidiary for operations and customer support through January 2018 during a portion of which period certain guarantees or other credit support provided by Con Edison in connection with the retail electric supply business continued in effect. See Note H. Upton 2 In May 2017, Con Edison Development sold Upton 2, a development stage solar electric production project, for $11 million to Vistra Asset Co. and recorded a $1 million gain on sale ($0.7 million, net of taxes). In addition, Con Edison Development agreed to perform the engineering, procurement and construction for the 180 MW (AC) project, which is expected to be substantially completed in 2018. |
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- References No definition available.
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- Definition The entire disclosure for business combinations, including leverage buyout transactions (as applicable), and divestitures. This may include a description of a business combination or divestiture (or series of individually immaterial business combinations or divestitures) completed during the period, including background, timing, and assets and liabilities recognized and reclassified or sold. This element does not include fixed asset sales and plant closings. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Schedule I - Condensed Financial Information |
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| Condensed Financial Information of Parent Company Only Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule I - Condensed Financial Information | Schedule I Condensed Financial Information of Consolidated Edison, Inc. (a) Condensed Statement of Income and Comprehensive Income (Parent Company Only)
Condensed Financial Information of Consolidated Edison, Inc. (a) Condensed Statement of Cash Flows (Parent Company Only)
Condensed Financial Information of Consolidated Edison, Inc. (a) Condensed Balance Sheet (Parent Company Only)
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- References No definition available.
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- Definition The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Schedule II - Valuation and Qualifying Accounts |
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| Schedule II - Valuation and Qualifying Accounts | Schedule II Valuation and Qualifying Accounts For the Years Ended December 31, 2017, 2016 and 2015
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- Definition The entire disclosure for any allowance and reserve accounts (their beginning and ending balances, as well as a reconciliation by type of activity during the period). Alternatively, disclosure of the required information may be within the footnotes to the financial statements or a supplemental schedule to the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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Summary of Significant Accounting Policies (Policies) |
12 Months Ended |
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Dec. 31, 2017 | |
| Accounting Policies [Abstract] | |
| Principles of Consolidation | Principles of Consolidation The Companies’ consolidated financial statements include the accounts of their respective majority-owned subsidiaries, and variable interest entities (see Note Q), as required. All intercompany balances and transactions have been eliminated. |
| Accounting Policies | Accounting Policies The accounting policies of Con Edison and its subsidiaries conform to generally accepted accounting principles in the United States of America (GAAP). For the Utilities, these accounting principles include the accounting rules for regulated operations and the accounting requirements of the Federal Energy Regulatory Commission (FERC) and the state regulators having jurisdiction. The accounting rules for regulated operations specify the economic effects that result from the causal relationship of costs and revenues in the rate-regulated environment and how these effects are to be accounted for by a regulated enterprise. Revenues intended to cover some costs may be recorded either before or after the costs are incurred. If regulation provides assurance that incurred costs will be recovered in the future, these costs would be recorded as deferred charges or “regulatory assets” under the accounting rules for regulated operations. If revenues are recorded for costs that are expected to be incurred in the future, these revenues would be recorded as deferred credits or “regulatory liabilities” under the accounting rules for regulated operations. The Utilities’ principal regulatory assets and liabilities are detailed in Note B. The Utilities are receiving or being credited with a return on all of their regulatory assets for which a cash outflow has been made, and are paying or being charged with a return on all of their regulatory liabilities for which a cash inflow has been received. The Utilities’ regulatory assets and liabilities will be recovered from customers, or applied for customer benefit, in accordance with rate provisions approved by the applicable state regulators. |
| Plant and Depreciation | Non–Utility Plant Non-utility plant is stated at original cost. For Con Edison, non–utility plant consists primarily of the Clean Energy Businesses’ renewable electric production and gas storage. For the Utilities, non–utility plant consists of land and conduit for telecommunication use. Depreciation on these assets is computed using the straight-line method for financial statement purposes over their estimated useful lives, which range from 3 to 30 years. Plant and Depreciation Utility Plant Utility plant is stated at original cost. The cost of repairs and maintenance is charged to expense and the cost of betterments is capitalized. The capitalized cost of additions to utility plant includes indirect costs such as engineering, supervision, payroll taxes, pensions, other benefits and an allowance for funds used during construction (AFUDC). The original cost of property is charged to expense over the estimated useful lives of the assets. Upon retirement, the original cost of property is charged to accumulated depreciation. See Note R. Rates used for AFUDC include the cost of borrowed funds and a reasonable rate of return on the Utilities’ own funds when so used, determined in accordance with regulations of the FERC or the state public utility regulatory authority having jurisdiction. The rate is compounded semiannually, and the amounts applicable to borrowed funds are treated as a reduction of interest charges, while the amounts applicable to the Utilities’ own funds are credited to other income (deductions). The AFUDC rates for CECONY were 5.5 percent, 4.7 percent and 4.4 percent for 2017, 2016 and 2015, respectively. The AFUDC rates for O&R were 2.5 percent, 3.5 percent and 0.4 percent for 2017, 2016 and 2015, respectively. The Utilities generally compute annual charges for depreciation using the straight-line method for financial statement purposes, with rates based on average service lives and net salvage factors. The average depreciation rates for CECONY were 3.1 percent for 2017, 2016 and 2015. The average depreciation rates for O&R were 2.9 percent for 2017 and 2016 and 3.0 percent for 2015. The estimated lives for utility plant for CECONY range from 5 to 95 years for electric, 5 to 100 years for gas, 5 to 80 years for steam and 5 to 55 years for general plant. For O&R, the estimated lives for utility plant range from 5 to 75 years for electric and gas and 5 to 50 years for general plant. |
| Goodwill | Goodwill Con Edison tests goodwill for impairment at least annually or whenever there is a triggering event. There is an option to first make a qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount before applying a two–step, quantitative goodwill impairment test. Con Edison has elected to perform the qualitative assessment for substantially all of its goodwill and, if needed, applies the two-step quantitative approach. The first step of the quantitative goodwill impairment test compares the estimated fair value of a reporting unit with its carrying value, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying value, goodwill of the reporting unit is considered not impaired. If the carrying value exceeds the estimated fair value of the reporting unit, the second step is performed to measure the amount of impairment loss, if any. The second step requires a calculation of the implied fair value of goodwill. |
| Long-Lived and Intangible Assets | Long–Lived and Intangible Assets Con Edison evaluates the impairment of long-lived assets and intangible assets with definite lives, based on projections of undiscounted future cash flows, whenever events or changes in circumstances indicate that the carrying amounts of such assets may not be recoverable. In the event an evaluation indicates that such cash flows cannot be expected to be sufficient to fully recover the assets, the assets are written down to their estimated fair value. |
| Revenues | Revenues The Utilities and Con Edison Solutions, until the sale of its retail electric supply business in September 2016 (see Note U), recognize revenues as energy is delivered to customers. The Utilities accrue and Con Edison Solutions accrued revenues at the end of each month for estimated energy not yet billed to customers. The Utilities defer over a 12–month period net interruptible gas revenues, other than those authorized by the NYSPSC to be retained by the Utilities, for refund to firm gas sales and transportation customers. Con Edison Development recognizes revenue for the sale of energy from renewable electric production projects as energy is generated and billed to counterparties. Con Edison Development accrues revenues at the end of each month for energy not yet billed to counterparties. Con Edison Energy recognizes revenue as energy is delivered and services are provided for managing energy supply assets leased from others and managing the dispatch, fuel requirements and risk management activities for generating plants and merchant transmission in the northeastern United States. Con Edison Solutions recognizes revenue for providing energy-efficiency services to government and commercial customers, and Con Edison Development recognizes revenue for the engineering, procurement and construction of Upton 2, under the percentage-of-completion method of revenue recognition. Sales and profits on each percentage-of-completion contract are recorded based on the ratio of actual cumulative costs incurred to the total estimated costs at completion of the contract, multiplied by the total estimated contract revenue, less cumulative sales recognized in prior periods (the ‘‘cost-to-cost’’ method). The impact of revisions of contract estimates, which may result from contract modifications, performance or other reasons, are recognized on a cumulative catch-up basis in the period in which the revisions are made. Unbilled contract revenues were $58 million and $21 million as of December 31, 2017 and 2016, respectively, and represent accumulated incurred costs and earned profits on contracts (revenue arrangements), which have been recorded as revenues, but have not yet been billed to customers. Substantially all unbilled contract revenues are expected to be collected within one year. Unbilled contract revenues arise from the cost-to-cost method of revenue recognition. Unbilled contract revenues from fixed-price type contracts are converted to billed receivables when amounts are invoiced to customers according to contractual billing terms, which generally occur when deliveries or other performance milestones are completed. Unearned revenue, which reflects a liability for billings to customers in excess of earned revenue was $87 million and $2 million as of December 31, 2017 and 2016, respectively. Revenues recorded as energy is delivered, generated or services provided and billed to customers are recorded in accounts receivable – customers. Con Edison's and the Utilities' accounts receivable – customers balance also reflects the Utilities' purchase of receivables from energy service companies to support retail choice programs. Accrued revenues not yet billed to customers are recorded as accrued unbilled revenues. CECONY’s electric and gas rate plans and O&R’s New York electric and gas rate plans each contain a revenue decoupling mechanism under which the company’s actual energy delivery revenues are compared with the authorized delivery revenues and the difference accrued, with interest, for refund to, or recovery from, customers, as applicable. See “Rate Plans” in Note B. The NYSPSC requires utilities to record gross receipts tax revenues and expenses on a gross income statement presentation basis (i.e., included in both revenue and expense). The recovery of these taxes is generally provided for in the revenue requirement within each of the respective NYSPSC approved rate plans. |
| Recoverable Energy Costs/New York Independent System Operator (NYISO) | Recoverable Energy Costs The Utilities generally recover all of their prudently incurred fuel, purchased power and gas costs, including hedging gains and losses, in accordance with rate provisions approved by the applicable state public utility regulators. If the actual energy supply costs for a given month are more or less than the amounts billed to customers for that month, the difference in most cases is recoverable from or refundable to customers. Differences between actual and billed electric and steam supply costs and costs of its electric demand management programs are generally deferred for charge or refund to customers during the next billing cycle (normally within one or two months). For the Utilities’ gas costs, differences between actual and billed gas costs during the 12–month period ending each August are charged or refunded to customers during a subsequent 12–month period. New York Independent System Operator (NYISO) The Utilities purchase electricity through the wholesale electricity market administered by the NYISO. The difference between purchased power and related costs initially billed to the Utilities by the NYISO and the actual cost of power subsequently calculated by the NYISO is refunded by the NYISO to the Utilities, or paid to the NYISO by the Utilities. The reconciliation payments or receipts are recoverable from or refundable to the Utilities’ customers. Certain other payments to or receipts from the NYISO are also subject to reconciliation, with shortfalls or amounts in excess of specified rate allowances recoverable from or refundable to customers. These include proceeds from the sale through the NYISO of transmission rights on CECONY’s transmission system (transmission congestion contracts or TCCs). |
| Temporary Cash Investments | Temporary Cash Investments Temporary cash investments are short-term, highly–liquid investments that generally have maturities of three months or less at the date of purchase. They are stated at cost, which approximates market. The Companies consider temporary cash investments to be cash equivalents. |
| Investments | Investments Investments consist primarily of the investments of Con Edison Transmission and the Clean Energy Businesses that are accounted for under the equity method, and the fair value of the Utilities’ supplemental retirement income plan and deferred income plan assets. |
| Pension and Other Postretirement Benefits | Pension and Other Postretirement Benefits The accounting rules for retirement benefits require an employer to recognize an asset or liability for the overfunded or underfunded status of its pension and other postretirement benefit plans. For a pension plan, the asset or liability is the difference between the fair value of the plan’s assets and the projected benefit obligation. For any other postretirement benefit plan, the asset or liability is the difference between the fair value of the plan’s assets and the accumulated postretirement benefit obligation. The accounting rules generally require employers to recognize all unrecognized prior service costs and credits and unrecognized actuarial gains and losses in accumulated other comprehensive income/(loss) (OCI), net of tax. Such amounts will be adjusted as they are subsequently recognized as components of total periodic benefit cost or income pursuant to the current recognition and amortization provisions. For the Utilities’ pension and other postretirement benefit plans, regulatory accounting treatment is generally applied in accordance with the accounting rules for regulated operations. Unrecognized prior service costs or credits and unrecognized actuarial gains and losses are recorded to regulatory assets or liabilities, rather than OCI. See Notes E and F. The total periodic benefit costs are recognized in accordance with the accounting rules for retirement benefits. Investment gains and losses are recognized in expense over a 15–year period and other actuarial gains and losses are recognized in expense over a 10–year period, subject to the deferral provisions in the rate plans. In accordance with the Statement of Policy issued by the NYSPSC and its current electric, gas and steam rate plans, CECONY defers for payment to or recovery from customers the difference between such expenses and the amounts for such expenses reflected in rates. Generally, O&R also defers such difference pursuant to its rate plans. See Note B. The Companies calculate the expected return on pension and other postretirement benefit plan assets by multiplying the expected rate of return on plan assets by the market-related value (MRV) of plan assets at the beginning of the year, taking into consideration anticipated contributions and benefit payments that are to be made during the year. The accounting rules allow the MRV of plan assets to be either fair value or a calculated value that recognizes changes in fair value in a systematic and rational manner over not more than five years. The Companies use a calculated value when determining the MRV of the plan assets that adjusts for 20 percent of the difference between fair value and expected MRV of plan assets. This calculated value has the effect of stabilizing variability in assets to which the Companies apply the expected return. |
| Federal Income Tax/State Income Tax | Federal Income Tax In accordance with accounting rules for income taxes, the Companies have recorded an accumulated deferred federal income tax liability at current tax rates for temporary differences between the book and tax basis of assets and liabilities. In accordance with rate plans, the Utilities have recovered amounts from customers for a portion of the tax liability they will pay in the future as a result of the reversal or “turn-around” of these temporary differences. As to the remaining deferred tax liability, the Utilities had established regulatory assets for the net revenue requirements to be recovered from customers for the related future tax expense pursuant to the NYSPSC's 1993 Policy Statement approving accounting procedures consistent with accounting rules for income taxes and providing assurances that these future increases in taxes will be recoverable in rates. Upon enactment of the Tax Cuts and Jobs Act of 2017 on December 22, 2017 (the TCJA), the Companies re-measured their deferred tax assets and liabilities based upon the 21 percent corporate income tax rate under the TCJA. As a result, Con Edison decreased its net deferred tax liabilities by $5,312 million (including $4,781 million for CECONY), recognized net income of $259 million, decreased its regulatory asset for future income tax by $1,250 million (including $1,182 million for CECONY), decreased its regulatory asset for revenue taxes by $90 million (including $86 million for CECONY), and accrued a regulatory liability for future income tax of $3,713 million (including $3,513 million for CECONY). See “Other Regulatory Matters” and “Regulatory Assets and Liabilities” in Note B and Note L. Accumulated deferred investment tax credits are amortized ratably over the lives of the related properties and applied as a reduction to future federal income tax expense. Con Edison and its subsidiaries file a consolidated federal income tax return. The consolidated income tax liability is allocated to each member of the consolidated group using the separate return method. Each member pays or receives an amount based on its own taxable income or loss in accordance with a consolidated tax allocation agreement. Tax loss and tax credit carryforwards are allocated among members in accordance with consolidated tax return regulations. State Income Tax Con Edison and its subsidiaries file a combined New York State Corporation Business Franchise Tax Return. Similar to a federal consolidated income tax return, the income of all entities in the combined group is subject to New York State taxation, after adjustments for differences between federal and New York law and apportionment of income among the states in which the company does business. Each member’s share of the New York State tax is based on its own New York State taxable income or loss. |
| Research and Development Costs | Research and Development Costs Research and development costs are charged to operating expenses as incurred. |
| Reclassification | Reclassification Certain prior year amounts have been reclassified to conform with the current year presentation. |
| Earnings Per Common Share | Earnings Per Common Share Con Edison presents basic and diluted earnings per share on the face of its consolidated income statement. Basic earnings per share (EPS) are calculated by dividing earnings available to common shareholders (“Net income” on Con Edison’s consolidated income statement) by the weighted average number of Con Edison common shares outstanding during the period. In the calculation of diluted EPS, weighted average shares outstanding are increased for additional shares that would be outstanding if potentially dilutive securities were converted to common stock. Potentially dilutive securities for Con Edison consist of restricted stock units and deferred stock units for which the average market price of the common shares for the period was greater than the exercise price. |
| Estimates | Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. |
| New Financial Accounting Standards | New Financial Accounting Standards In January 2018, the Companies adopted Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” including the amendments thereto, (the New Standard) using the modified retrospective approach the New Standard permitted. The New Standard supersedes the revenue recognition requirements within Accounting Standards Codification Topic 605, “Revenue Recognition,” and most industry-specific guidance (the Superseded Standard). The purpose of the New Standard is to create a consistent framework for revenue recognition. The New Standard clarifies how to measure and recognize revenue arising from customer contracts to depict the transfer of goods or services in an amount that reflects the consideration the entity expects to receive. The New Standard also clarifies key areas including principal/agent considerations, performance obligations, licensing, sales taxes, noncash consideration, and contracts. The majority of Con Edison’s’ revenues and substantially all of CECONY’s revenues are derived from the provision of electric, gas, and steam service to customers pursuant to the terms of tariffs approved by the NYSPSC or NJBPU. For such service, the Companies expect that the revenue from contracts with customers for a period that will be recorded under the New Standard will be equivalent to the revenue for the period that would have been recorded under the Superseded Standard. Most of Con Edison’s other revenues are derived from the Clean Energy Businesses’ sale of energy-related products and services, operation of renewable and energy infrastructure projects, and sale of renewable energy credits. For such businesses, Con Edison expects that the revenue from contracts with customers for a period that will be recorded under the New Standard will not be materially different from the revenue for the period that would have been recorded under the Superseded Standard. Under the modified retrospective method of adoption, prior year reported results are not restated and a cumulative-effect adjustment, if applicable, is recorded to retained earnings at January 1, 2018. As of January 1, 2018, the cumulative-effect adjustment was not material to the Companies. The Companies also plan to use certain practical expedients including applying this guidance to open contracts at the date of adoption and recognizing revenues for certain contracts under the invoice practical expedient. Such expedients allow revenue recognition to be consistent with invoiced amounts (including estimated billings) provided certain criteria are met, including consideration of whether the invoiced amounts reasonably represent the value provided to customers. The adoption of the New Standard will not have a material impact on the Companies’ financial statements, results of operations, and liquidity, including the presentation of revenues in their consolidated income statements. The adoption of the New Standard will not require a change in the Companies’ internal control over financial reporting that is reasonably likely to materially affect their internal control over financial reporting. In February 2016, the FASB issued amendments on financial reporting of leasing transactions through ASU No. 2016-02, “Leases (Topic 842)." The amendments require lessees to recognize assets and liabilities on the balance sheet and disclose key information about leasing arrangements. Lessees will need to recognize a right-of-use asset and a lease liability for virtually all of their leases (other than leases that meet the definition of a short-term lease). Lessor accounting is similar to the current model, but updated to align with certain changes to the lessee model. For income statement purposes, the pattern of expense recognition will depend on whether transactions are designated as operating leases or finance leases. In January 2018, the FASB issued amendments on the lease standard’s application to land easements through ASU No. 2018-01, “Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842.” The amendments allow an entity to not evaluate under Topic 842 land easements that exist or expired before the entity’s adoption of Topic 842 and that were not previously accounted for as leases under the current lease standard. The amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The amendments must be adopted using a modified retrospective transition and provide for certain practical expedients. Based on the existing portfolio of leases at implementation, for leases currently classified as operating leases, the Companies expect to recognize on the statements of financial position right-of-use assets and lease liabilities. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ results of operations and liquidity. In January 2017, the FASB issued amendments to the guidance for Business Combinations through ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” The amendments in this update clarify the definition of a business and provide guidance on evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In January 2017, the FASB issued amendments to the guidance for the subsequent measurement of goodwill through ASU 2017-04, “Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The amendments in this update simplify goodwill impairment testing by eliminating Step 2 of the goodwill impairment test wherein an entity has to compute the implied fair value of goodwill by performing procedures to determine the fair value of its assets and liabilities. Under the new guidance, an entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value up to the total amount of goodwill allocated to that reporting unit. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In February 2017, the FASB issued amendments to the guidance for other income through ASU 2017-05, “Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets.” The amendments in this update clarify the scope of assets within Subtopic 610-20 and add guidance for partial sales of nonfinancial assets. The amendments are effective upon the adoption of ASU 2014-09, and therefore will be effective for reporting periods beginning after December 15, 2017. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2017, the FASB issued amendments to the guidance for retirement benefits through ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” The amendments in this update modify the presentation of net benefit cost, where the service component must be disaggregated from the other components of net benefit cost and be presented in the same line item as current employee compensation costs. The remaining components of the net benefit cost should be presented outside of income from operations. Additionally, the update allows only the service cost component to be eligible for capitalization. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017. The guidance allows a practical expedient that permits the use of amounts disclosed in prior-period financial statements as appropriate estimates when applying the presentation requirements retrospectively. The Companies have elected to use the practical expedient under ASU 2017-07. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In March 2017, the FASB issued amendments to the guidance for debt securities through ASU 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” The amendments in this update shorten the amortization period for certain callable debt securities held at a premium. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. For public entities, the amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In May 2017, the FASB issued amendments to the guidance for stock compensation through ASU 2017-09, “Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting.” The amendments in this update specify that changes to value, vesting conditions, or classification of an existing share-based payment award require application of modification accounting in Topic 718. For public entities, the amendments are effective for reporting periods beginning after December 15, 2017.The application of this guidance is not expected to have a material impact on the Companies’ financial position, results of operations and liquidity. In August 2017, the FASB issued amendments to the guidance for derivatives and hedging through ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities.” The amendments in this update provide greater clarification on hedge accounting for risk components, presentation and disclosure of hedging instruments, and overall targeted improvements to simplify hedge accounting. For public entities, the amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ financial position, results of operations and liquidity. In February 2018, the FASB issued amendments to the guidance for reporting comprehensive income through ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” The amendments allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the TCJA. For public entities, the amendments are effective for reporting periods beginning after December 15, 2018. Early adoption is permitted. The Companies are in the process of evaluating the potential impact of the new guidance on the Companies’ financial position, results of operations and liquidity. |
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- Definition Disclosure of accounting policy for basis of accounting, or basis of presentation, used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS). No definition available.
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- Definition Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for salaries, bonuses, incentive awards, postretirement and postemployment benefits granted to employees, including equity-based arrangements; discloses methodologies for measurement, and the bases for recognizing related assets and liabilities and recognizing and reporting compensation expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for goodwill and intangible assets. This accounting policy also may address how an entity assesses and measures impairment of goodwill and intangible assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for recognizing and measuring the impairment of long-lived assets. An entity also may disclose its accounting policy for long-lived assets to be sold. This policy excludes goodwill and intangible assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for investments in financial assets, including marketable securities (debt and equity securities with readily determinable fair values), investments accounted for under the equity method and cost method, securities borrowed and loaned, and repurchase and resale agreements. For marketable securities, the disclosure may include the entity's accounting treatment for transfers between investment categories and how the fair values for such securities are determined. Also, for all investments, an entity may describe its policy for assessing, recognizing and measuring impairment of the investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for long-lived, physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, basis of assets, depreciation and depletion methods used, including composite deprecation, estimated useful lives, capitalization policy, accounting treatment for costs incurred for repairs and maintenance, capitalized interest and the method it is calculated, disposals and impairments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for public utilities. Examples include a discussion about the scope criteria and appropriateness for and extent of the application of generally accepted accounting principles related to accounting for the effects of certain types of regulation (may include identification of specific business units). Other examples of the disclosures may include: descriptions of the form and economic effects of regulation (for example, but not limited to, recording of regulatory assets and liabilities to the rate setting process); statement about periodic assessments of periodic assessments of generally accepted accounting principles related to accounting for the effects of certain types of regulation; information regarding amortization of and return on regulatory assets and liabilities, including the remaining amounts and recovery or settlement periods; accounting for changes to recovery estimates; AFUDC, plant abandonment's and plant disallowances. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for its research and development and computer software activities including the accounting treatment for costs incurred for (1) research and development activities, (2) development of computer software for internal use, (3) computer software to be sold, leased or otherwise marketed as a separate product or as part of a product or process and (4) in-process research and development acquired in a purchase business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Summary of Significant Accounting Policies (Tables) |
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| Accounting Policies [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Capitalized Cost of Utility Plant | At December 31, 2017 and 2016, the capitalized cost of the Companies’ utility plant, net of accumulated depreciation, was as follows:
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| Schedule of Total Excise Taxes Recorded in Operating Revenues | Total excise taxes (inclusive of gross receipts taxes) recorded in operating revenues were as follows:
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| Schedule of Investment Assets | The following investment assets are included in the Companies' consolidated balance sheets at December 31, 2017 and 2016:
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| Research and Development Costs | Research and development costs were as follows:
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| Basic and Diluted EPS | Basic and diluted EPS for Con Edison are calculated as follows:
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| Changes in Accumulated Other Comprehensive Income/(Loss) | Changes to accumulated other comprehensive income/(loss) (OCI) for Con Edison and CECONY are as follows:
(b) For the portion of unrecognized pension and other postretirement benefit costs relating to the Utilities, costs are recorded into, and amortized out of, regulatory assets instead of OCI. The net actuarial losses and prior service costs recognized during the period are included in the computation of total periodic pension and other postretirement benefit cost. See Notes E and F. |
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- Definition Schedule Of Excise Taxes [Table Text Block] No definition available.
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- Definition Schedule Of Research And Development Expense Table [Text Block] No definition available.
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- References No definition available.
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- Definition Tabular disclosure of equity method investments including, but not limited to, name of each investee or group of investments, percentage ownership, difference between recorded amount of an investment and the value of the underlying equity in the net assets, and summarized financial information. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the components of accumulated other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the effect of income (loss) on an entity's diluted earnings per share. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of public utility physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, deprecation expense and method used, including composite depreciation, and accumulated deprecation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Regulatory Matters (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Regulated Operations [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Utilities Rate Plans |
The following tables contain a summary of the Utilities’ rate plans:
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| Schedule of Regulatory Assets | Regulatory assets and liabilities at December 31, 2017 and 2016 were comprised of the following items:
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| Schedule of Regulatory Liabilities | Regulatory assets and liabilities at December 31, 2017 and 2016 were comprised of the following items:
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- Definition Tabular disclosure of regulation for public utility entities, including, but not limited to, rate requests, decommissioning costs and the amount of allowance for earnings on equity capitalized for rate making purposes. No definition available.
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- References No definition available.
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- Definition Tabular disclosure of assets that are created when regulatory agencies permit public utilities to defer certain costs included in rate-setting to the balance sheet. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of regulatory liabilities. Detailed information about liabilities that result from rate actions of a regulator. Rate actions of a regulator can impose a liability on a regulated enterprise resulting in a regulatory liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Capitalization (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Debt Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Long-Term Debt Maturities | Long-term debt maturing in the period 2018-2022 is as follows:
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| Carrying Amounts and Fair Values of Long-Term Debt | The carrying amounts and fair values of long-term debt at December 31, 2017 and 2016 are:
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- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of information pertaining to carrying amount and estimated fair value of short-term and long-term debt instruments or arrangements, including but not limited to, identification of terms, features, and collateral requirements. No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Pension Benefits (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Retirement Benefits [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Total Periodic Benefit Costs | The components of the Companies’ total periodic benefit costs for 2017, 2016 and 2015 were as follows:
(a) Relates to an increase in CECONY’s pension obligation of $45 million from a 1999 special retirement program. The components of the Companies’ total periodic postretirement benefit costs for 2017, 2016 and 2015 were as follows:
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| Schedule of Funded Status | The funded status at December 31, 2017, 2016 and 2015 was as follows:
The funded status of the programs at December 31, 2017, 2016 and 2015 were as follows:
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| Schedule of Assumptions | The actuarial assumptions were as follows:
The actuarial assumptions were as follows:
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| Schedule of Expected Benefit Payments | Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years:
Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years, net of receipt of governmental subsidies:
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| Schedule of Plan Assets Allocations | The asset allocations for the pension plan at the end of 2017, 2016 and 2015, and the target allocation for 2018 are as follows:
The asset allocations for CECONY’s other postretirement benefit plans at the end of 2017, 2016 and 2015, and the target allocation for 2018 are as follows:
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| Schedule of Fair Value of Plan Assets | The fair values of the pension plan assets at December 31, 2017 by asset category are as follows:
The fair values of the pension plan assets at December 31, 2016 by asset category are as follows:
The fair values of the plan assets at December 31, 2017 by asset category as defined by the accounting rules for fair value measurements (see Note P) are as follows:
The fair values of the plan assets at December 31, 2016 by asset category (see Note P) are as follows:
(a) - (f) Reference is made to footnotes (a) through (f) in the above table of other postretirement benefit plan assets at December 31, 2017 by asset category. |
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| Schedule of Employer Contribution to Defined Savings Plan | The Companies also offer a defined contribution savings plan that covers substantially all employees and made contributions to the plan as follows:
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of defined contribution pension plans or defined contribution other postretirement plans, separately for pension plans and other postretirement benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the amounts that are recognized in the balance sheet (or statement of financial position) for pension plans and/or other employee benefit plans, showing separately the assets and current and noncurrent liabilities (if applicable) recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the benefit obligation and net benefit cost, including assumed discount rates, rate increase in compensation increase, and expected long-term rates of return on plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of net funded status of pension plans and/or other employee benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Other Postretirement Benefits (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Retirement Benefits [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Net Periodic Benefit Costs | The components of the Companies’ total periodic benefit costs for 2017, 2016 and 2015 were as follows:
(a) Relates to an increase in CECONY’s pension obligation of $45 million from a 1999 special retirement program. The components of the Companies’ total periodic postretirement benefit costs for 2017, 2016 and 2015 were as follows:
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| Schedule of Funded Status | The funded status at December 31, 2017, 2016 and 2015 was as follows:
The funded status of the programs at December 31, 2017, 2016 and 2015 were as follows:
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| Schedule of Actuarial Assumptions | The actuarial assumptions were as follows:
The actuarial assumptions were as follows:
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| Schedule of Change of Assumed Health Care Cost Trend Rate | A one-percentage point change in the assumed health care cost trend rate would have the following effects at December 31, 2017:
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| Schedule of Expected Benefit Payments | Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years:
Based on current assumptions, the Companies expect to make the following benefit payments over the next ten years, net of receipt of governmental subsidies:
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| Schedule of Plan Assets Allocations | The asset allocations for the pension plan at the end of 2017, 2016 and 2015, and the target allocation for 2018 are as follows:
The asset allocations for CECONY’s other postretirement benefit plans at the end of 2017, 2016 and 2015, and the target allocation for 2018 are as follows:
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| Schedule of Fair Value of Plan Assets | The fair values of the pension plan assets at December 31, 2017 by asset category are as follows:
The fair values of the pension plan assets at December 31, 2016 by asset category are as follows:
The fair values of the plan assets at December 31, 2017 by asset category as defined by the accounting rules for fair value measurements (see Note P) are as follows:
The fair values of the plan assets at December 31, 2016 by asset category (see Note P) are as follows:
(a) - (f) Reference is made to footnotes (a) through (f) in the above table of other postretirement benefit plan assets at December 31, 2017 by asset category. |
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the amounts that are recognized in the balance sheet (or statement of financial position) for pension plans and/or other employee benefit plans, showing separately the assets and current and noncurrent liabilities (if applicable) recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the benefit obligation and net benefit cost, including assumed discount rates, rate increase in compensation increase, and expected long-term rates of return on plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the effect of a one-percentage-point increase and the effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs and the accumulated postretirement benefit obligation for health care benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of net funded status of pension plans and/or other employee benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Environmental Matters (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Environmental Remediation Obligations [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Accrued Liabilities and Regulatory Assets | The accrued liabilities and regulatory assets related to Superfund Sites at December 31, 2017 and 2016 were as follows:
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| Environmental Remediation Costs | Environmental remediation costs incurred related to Superfund Sites at December 31, 2017 and 2016 were as follows:
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| Accrued Liability for Asbestos Suits and Workers' Compensation Proceedings | The accrued liability for asbestos suits and workers’ compensation proceedings (including those related to asbestos exposure) and the amounts deferred as regulatory assets for the Companies at December 31, 2017 and 2016 were as follows:
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| X | ||||||||||
- Definition Accrued Liabilities And Regulatory Assets [Table Text Block] No definition available.
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| X | ||||||||||
- Definition Accrued liabilities for asbestos suits and workers compensation proceedings. No definition available.
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| X | ||||||||||
- Definition Environmental Remediation Costs Incurred Related To Super Fund Sites [Table Text Block] No definition available.
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| X | ||||||||||
- References No definition available.
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Other Material Contingencies (Tables) |
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Commitments and Contingencies Disclosure [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Total Guarantees | A summary, by type and term, of Con Edison’s total guarantees at December 31, 2017 is as follows:
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of each guarantee obligation, or each group of similar guarantee obligations, including (a) the nature of the guarantee, including its term, how it arose, and the events or circumstances that would require the guarantor to perform under the guarantee; (b) the maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee; (c) the current carrying amount of the liability, if any, for the guarantor's obligations under the guarantee; and (d) the nature of any recourse provisions under the guarantee, and any assets held either as collateral or by third parties, and any relevant related party disclosure. Excludes disclosures about product warranties. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Electricity Purchase Agreements (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Regulated Operations [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Significant Terms of Electricity Purchase Agreements | At December 31, 2017, the significant terms of the electricity purchase agreements with non-utility generators were as follows:
(a) A portion of this contract ended in 2017 and a portion ends in 2018. |
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| Summary of Estimated Capacity and Other Fixed Payments | The future capacity and other fixed payments under the contracts are estimated to be as follows:
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| Summary of Capacity, Energy and Other Fixed Payments | The company’s payments under the significant terms of the agreements for capacity, energy and other fixed payments in 2017, 2016 and 2015 were as follows:
(a) Contract term ended in 2017. (b) Contract term ended in 2016. (c) Contract term ended in 2015. |
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- Definition Estimated Aggregate Amounts Of Minimum Fixed Payments On Purchase And Service Obligations Table [Text Block] No definition available.
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- Definition Schedule Of Fixed Capacity Payment Commitments Table [Text Block] No definition available.
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- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of information concerning the terms and significance of long term contracts to purchase power (generally referred to as purchase power agreements (PPAs) or power sale agreements (PSAs)) including date of contract expiration, share of plant output being purchased, estimated annual cost, annual minimum debt service payment required and amount of related long-term debt or lease obligations outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Leases (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||
| Leases [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Capital Leases | The following assets under capital leases are included in the Companies’ consolidated balance sheets at December 31, 2017 and 2016:
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| Future Minimum Rental Payments for Operating Leases | The future minimum lease commitments under the Companies’ operating lease agreements that are not cancellable by the Companies are as follows:
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- References No definition available.
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- Definition Tabular disclosure of long-lived, depreciable assets that are subject to a lease meeting the criteria for capitalization and are used in the normal conduct of business to produce goods and services. Examples may include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of future minimum payments required in the aggregate and for each of the five succeeding fiscal years for operating leases having initial or remaining noncancelable lease terms in excess of one year and the total minimum rentals to be received in the future under noncancelable subleases as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Income Tax (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Income Tax Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Components of Income Tax | The components of income tax are as follows:
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| Schedule of Differences on Deferred Tax Assets and Liabilities | The tax effects of temporary differences, which gave rise to deferred tax assets and liabilities, are as follows:
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| Schedule of Income Tax Reconciliation | Reconciliation of the difference between income tax expense and the amount computed by applying the prevailing statutory income tax rate to income before income taxes is as follows:
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| Summary of Unrecognized Tax Benefits | A reconciliation of the beginning and ending amounts of unrecognized tax benefits for Con Edison and CECONY follows:
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- References No definition available.
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- Definition Tabular disclosure of the components of income tax expense attributable to continuing operations for each year presented including, but not limited to: current tax expense (benefit), deferred tax expense (benefit), investment tax credits, government grants, the benefits of operating loss carryforwards, tax expense that results from allocating certain tax benefits either directly to contributed capital or to reduce goodwill or other noncurrent intangible assets of an acquired entity, adjustments of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity, and adjustments of the beginning-of-the-year balances of a valuation allowance because of a change in circumstances that causes a change in judgment about the realizability of the related deferred tax asset in future years. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the components of net deferred tax asset or liability recognized in an entity's statement of financial position, including the following: the total of all deferred tax liabilities, the total of all deferred tax assets, the total valuation allowance recognized for deferred tax assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure for tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities and other income tax contingencies. Includes, but is not limited to, interest and penalties, reconciliation of unrecognized tax benefits, unrecognized tax benefits that would affect the effective tax rate, tax years that remain subject to examination by tax jurisdictions, and information about positions for which it is reasonably possible that amounts unrecognized will significantly change within 12 months. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Stock-Based Compensation (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of Stock-Based Compensation Expense | The following table summarizes stock-based compensation expense recognized by the Companies in the years ended December 31, 2017, 2016 and 2015:
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| Assumptions Used to Calculate Fair Value of Awards | The assumptions used to calculate the fair value of the awards were as follows:
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| Summary of Changes in Status of Performance RSUs | A summary of changes in the status of the Performance RSUs’ TSR and non-TSR portions during the year ended December 31, 2017 is as follows:
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| Summary of Changes in Status of Time-Based Awards | A summary of changes in the status of time-based awards during the year ended December 31, 2017 is as follows:
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- Definition Summary of Changes in Status of Time Based Awards Table [Text Block] No definition available.
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- References No definition available.
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- Definition Tabular disclosure of components of a stock option or other award plan under which equity-based compensation is awarded to employees, typically comprised of the amount of unearned compensation (deferred compensation cost), compensation expense, and changes in the quantity and fair value of the shares (or other type of equity) granted, exercised, forfeited, and issued and outstanding pertaining to that plan. Disclosure may also include nature and general terms of such arrangements that existed during the period and potential effects of those arrangements on shareholders, effect of compensation cost arising from equity-based payment arrangements on the income statement, method of estimating the fair value of the goods or services received, or the fair value of the equity instruments granted, during the period, cash flow effects resulting from equity-based payment arrangements and, for registrants that accelerate vesting of out of the money share options, reasons for the decision to accelerate. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the changes in outstanding nonvested restricted stock shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Financial Information by Business Segment (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Segment Reporting [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Financial Data for Business Segments | The financial data for the business segments are as follows:
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- Definition Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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Derivative Instruments and Hedging Activities (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Derivative Instruments and Hedging Activities Disclosure [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Offsetting of Assets | The fair values of the Companies’ commodity derivatives including the offsetting of assets and liabilities on the consolidated balance sheet at December 31, 2017 and 2016 were:
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| Offsetting of Liabilities | The fair values of the Companies’ commodity derivatives including the offsetting of assets and liabilities on the consolidated balance sheet at December 31, 2017 and 2016 were:
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| Realized and Unrealized Gains or Losses on Commodity Derivatives | The following table presents the realized and unrealized gains or losses on commodity derivatives that have been deferred or recognized in earnings for the years ended December 31, 2017 and 2016:
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| Hedged Volume of Derivative Transactions | The following table presents the hedged volume of Con Edison’s and CECONY’s derivative transactions at December 31, 2017:
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| Aggregate Fair Value of Companies' Derivative Instruments with Credit-Risk-Related Contingent Features | The following table presents the aggregate fair value of the Companies’ derivative instruments with credit-risk-related contingent features that are in a net liability position, the collateral posted for such positions and the additional collateral that would have been required to be posted had the lowest applicable credit rating been reduced one level and to below investment grade at December 31, 2017:
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of credit derivatives which includes information by sellers of credit derivatives, about each credit derivative, or each group of similar credit derivatives, including (a) the nature of the credit derivative - its term, how it arose, the events or circumstances that would require the seller to perform under the credit derivative, and the current status of the payment/performance risk of the credit derivative; (b) the maximum potential amount of future payments (undiscounted) the seller could be required to make under the credit derivative; (c) the current fair value of the credit derivative; and (d) the nature of any recourse provisions under the credit derivative, and any assets held either as collateral or by third parties. A credit derivative is a derivative instrument (1) in which one or more of its underlyings are related to the credit risk of a specified entity (or a group of entities) or an index based on the credit risk of a group of entities and (2) that exposes the seller to potential loss from credit-risk-related events specified in the contract. Examples of credit derivatives within the scope of this paragraph include, but are not limited to, credit default swaps, credit spread options, and credit index products; also includes a hybrid instrument that has an embedded credit derivative (for example, but not limited to, a credit-linked note). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of derivative and other financial assets that are subject to offsetting, including master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of derivative and other financial liabilities that are subject to offsetting, including master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the location and amount of derivative instruments and nonderivative instruments designated as hedging instruments reported before netting adjustments, and the amount of gain (loss) on derivative instruments and nonderivative instruments designated and qualified as hedging instruments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements (Tables) |
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Fair Value Disclosures [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assets and Liabilities Measured at Fair Value on Recurring Basis | Assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2017 and 2016 are summarized below.
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| Schedule of Commodity Derivatives |
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| Reconciliation of Beginning and Ending Net Balances for Assets and Liabilities Measured at Level 3 Fair Value | The table listed below provides a reconciliation of the beginning and ending net balances for assets and liabilities measured at fair value for the years ended December 31, 2017 and 2016 and classified as Level 3 in the fair value hierarchy:
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of quantitative information about the inputs used in the fair value measurement of assets. This disclosure may include, but is not limited to, the fair value of the asset, valuation technique used to measure fair value, the inputs used to measure fair value, the ranges of the inputs, and the weighted averages of the inputs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) using recurring unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Variable Interest Entities (Tables) |
12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Equity Method Investments and Joint Ventures [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Business Acquisitions, by Acquisition |
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| Summary of VIEs | The following table summarizes the VIEs in which Con Edison Development has entered into as of December 31, 2017:
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of a material business combination completed during the period, including background, timing, and recognized assets and liabilities. This table does not include leveraged buyouts. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Related Party Transactions (Tables) |
12 Months Ended | ||||||||||||||||||||||||
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Dec. 31, 2017 | |||||||||||||||||||||||||
| Related Party Transactions [Abstract] | |||||||||||||||||||||||||
| Summary of Costs of Administrative and Other Services Provided and Received | The costs of administrative and other services provided by CECONY to, and received by it from, Con Edison and its other subsidiaries for the years ended December 31, 2017, 2016 and 2015 were as follows:
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Tabular disclosure of related party transactions. Examples of related party transactions include, but are not limited to, transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners and (d) affiliates. No definition available.
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General (Details) |
12 Months Ended |
|---|---|
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Dec. 31, 2017
subsidiary
registrant
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| Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
| Number of registrants | registrant | 2 |
| Number of regulated subsidiaries | subsidiary | 2 |
| X | ||||||||||
- Definition Number of Registrants No definition available.
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| X | ||||||||||
- Definition Number of Regulated Subsidiaries No definition available.
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| X | ||||||||||
- References No definition available.
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Summary of Significant Accounting Policies - Plant and Depreciation (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Annual aggregate depreciation allowance | $ 1,253 | ||
| Non-Utility Plant | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 3 years | ||
| Non-Utility Plant | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 30 years | ||
| CECONY | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| AFUDC rates (percent) | 5.50% | 4.70% | 4.40% |
| Average depreciation rates (percent) | 3.10% | 3.10% | 3.10% |
| Annual aggregate depreciation allowance | $ 1,184 | ||
| CECONY | Electric | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 5 years | ||
| CECONY | Electric | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 95 years | ||
| CECONY | Gas | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 5 years | ||
| CECONY | Gas | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 100 years | ||
| CECONY | Steam | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 5 years | ||
| CECONY | Steam | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 80 years | ||
| CECONY | General Plant | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 5 years | ||
| CECONY | General Plant | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 55 years | ||
| O&R | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| AFUDC rates (percent) | 2.50% | 3.50% | 0.40% |
| Average depreciation rates (percent) | 2.90% | 2.90% | 3.00% |
| O&R | Electric | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 5 years | ||
| O&R | Electric | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 75 years | ||
| O&R | Gas | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 5 years | ||
| O&R | Gas | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 75 years | ||
| O&R | General Plant | Minimum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 5 years | ||
| O&R | General Plant | Maximum | |||
| Public Utility, Property, Plant and Equipment [Line Items] | |||
| Estimated useful lives (years) | 50 years | ||
| X | ||||||||||
- Definition Public Utilities, Depreciation Allowance, Current Rate Plans No definition available.
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| X | ||||||||||
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. No definition available.
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| X | ||||||||||
- Definition Effective rate, including composite rate, of cost of financing additions to qualifying regulated assets, commonly called allowance for funds used during construction. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Composite depreciation rate for public utility plants in service. No definition available.
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies - Capitalized Cost of Utility Plant (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| General | $ 3,008 | $ 2,719 |
| Held for future use | 76 | 74 |
| Construction work in progress | 1,605 | 1,175 |
| NET UTILITY PLANT | 35,273 | 33,045 |
| Electric Generation | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Generation | 544 | 479 |
| Electric Transmission | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Transmission | 3,210 | 3,184 |
| Electric Distribution | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Distribution | 18,959 | 18,150 |
| Gas | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Gas | 6,976 | 6,285 |
| Steam | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Steam | 1,798 | 1,882 |
| General | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| General | 2,105 | 1,816 |
| CECONY | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| General | 2,753 | 2,490 |
| Held for future use | 67 | 65 |
| Construction work in progress | 1,502 | 1,104 |
| NET UTILITY PLANT | 33,205 | 31,115 |
| CECONY | Electric Generation | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Generation | 544 | 479 |
| CECONY | Electric Transmission | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Transmission | 2,990 | 2,963 |
| CECONY | Electric Distribution | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Distribution | 17,996 | 17,234 |
| CECONY | Gas | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Gas | 6,403 | 5,749 |
| CECONY | Steam | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| Steam | 1,798 | 1,882 |
| CECONY | General | ||
| Public Utility, Property, Plant and Equipment [Line Items] | ||
| General | $ 1,905 | $ 1,639 |
| X | ||||||||||
- Definition Public Utilities Property Plant And Equipment Steam No definition available.
|
| X | ||||||||||
- Definition Discloses the period end amount of plants held for future use and whether such amount is included in the utility's rate base. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to regulated assets common to business units. No definition available.
|
| X | ||||||||||
- Definition Period end amount of construction work in progress in public utility. No definition available.
|
| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to utility distribution. No definition available.
|
| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to fuels owned by the public utility. No definition available.
|
| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to generation or processing owned by public utility. No definition available.
|
| X | ||||||||||
- Definition Period end amount of total net PPE. No definition available.
|
| X | ||||||||||
- Definition Period end amount of property, plant and equipment (PPE) related to utility transmission owned by public utility. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies - Goodwill (Details) |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
USD ($)
| |
| Accounting Policies [Abstract] | |
| Goodwill, impairment charge | $ 0 |
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
Summary of Significant Accounting Policies - Long-Lived and Intangible Assets (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Impaired Long-Lived Assets Held and Used [Line Items] | |||
| Impairment charges on long-lived assets | $ 0 | $ 0 | |
| Impairment charges on definite lived intangible assets | $ 0 | $ 0 | $ 0 |
| Discontinued Operations, Held-for-sale | Pike | |||
| Impaired Long-Lived Assets Held and Used [Line Items] | |||
| Impairment charge on assets held for sale | $ 5,000,000 | ||
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies - Revenues (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Accounting Policies [Abstract] | ||
| Revenue deferral period (months) | 12 months | |
| Unbilled contracts receivable | $ 58 | $ 21 |
| Billings in excess of earned revenue | $ 87 | $ 2 |
| X | ||||||||||
- Definition Recognition of Deferred Revenue, Period No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Liability attributable to (i) billings in excess of costs under the percentage of completion contract accounting method representing the difference between contractually invoiced amounts (billings) and revenue recognized based, for example, on costs incurred to estimated total costs at period end or (ii) contractually invoiced amounts (billings) in excess of costs incurred and accumulated under the completed contract accounting method. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
Summary of Significant Accounting Policies - Schedule of Total Excise Taxes Recorded in Operating Revenues (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Schedule of Excise Taxes [Line Items] | |||
| Excise taxes | $ 302 | $ 336 | $ 354 |
| CECONY | |||
| Schedule of Excise Taxes [Line Items] | |||
| Excise taxes | $ 292 | $ 316 | $ 331 |
| X | ||||||||||
- Definition Schedule of Excise Taxes [Line Items] No definition available.
|
| X | ||||||||||
- Definition The excise taxes collected by a public utility and reported in revenues if the amount of excise taxes is equal to 1 percent or more of such total. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
Summary of Significant Accounting Policies - Recoverable Energy Costs (Details) |
12 Months Ended |
|---|---|
Dec. 31, 2017 | |
| Minimum | |
| Public Utilities, General Disclosures [Line Items] | |
| Recovery or refund of energy costs, deferral period | 1 month |
| Maximum | |
| Public Utilities, General Disclosures [Line Items] | |
| Recovery or refund of energy costs, deferral period | 2 months |
| X | ||||||||||
- Definition Public Utilities, Recovery Costs, Deferral Period One No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies - Investments (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | $ 467 | $ 488 |
| Supplemental retirement income plan assets | 330 | 273 |
| Deferred income plan assets | 73 | 60 |
| Other | 9 | 9 |
| Total investments | 2,001 | 1,921 |
| CET | Stagecoach Gas Services, LLC | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | 971 | 992 |
| CET | Mountain Valley Pipeline LLC | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | 98 | 48 |
| CET | New York Transco, LLC | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | 53 | 51 |
| CECONY | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | 0 | 0 |
| Supplemental retirement income plan assets | 301 | 246 |
| Deferred income plan assets | 73 | 60 |
| Other | 9 | 9 |
| Total investments | 383 | 315 |
| CECONY | CET | Stagecoach Gas Services, LLC | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | 0 | 0 |
| CECONY | CET | Mountain Valley Pipeline LLC | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | 0 | 0 |
| CECONY | CET | New York Transco, LLC | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Equity method investments | $ 0 | $ 0 |
| X | ||||||||||
- Definition Supplemental Retirement Income Plan Assets No definition available.
|
| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of assets held under deferred compensation agreements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of long-term investments classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies - Pension and Other Postretirement Benefits (Details) |
12 Months Ended |
|---|---|
Dec. 31, 2017 | |
| Accounting Policies [Abstract] | |
| Investment gains and losses recognized, time period (years) | 15 years |
| Other actuarial gains and losses recognized, time period (years) | 10 years |
| Difference between fair value and expected market related value of plan assets (percent) | 20.00% |
| X | ||||||||||
- Definition Difference between fair value and expected market related value of plan assets No definition available.
|
| X | ||||||||||
- Definition Pension actuarial gains and losses recognized time period. No definition available.
|
| X | ||||||||||
- Definition Pension investment gains and losses recognized time period. No definition available.
|
| X | ||||||||||
- References No definition available.
|
Summary of Significant Accounting Policies - Federal Income Tax (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
USD ($)
| |
| Income Taxes Disclosure [Line Items] | |
| Decrease in net deferred tax liabilities resulting from TCJA | $ 5,312 |
| Change in net income resulting from TCJA | 259 |
| Future Income Tax | |
| Income Taxes Disclosure [Line Items] | |
| Increase in regulatory liability resulting from TCJA | 3,713 |
| Future Income Tax | |
| Income Taxes Disclosure [Line Items] | |
| Decrease in regulatory asset resulting from TCJA | 1,250 |
| Revenue Taxes | |
| Income Taxes Disclosure [Line Items] | |
| Decrease in regulatory asset resulting from TCJA | 90 |
| CECONY | |
| Income Taxes Disclosure [Line Items] | |
| Decrease in net deferred tax liabilities resulting from TCJA | 4,781 |
| CECONY | Future Income Tax | |
| Income Taxes Disclosure [Line Items] | |
| Increase in regulatory liability resulting from TCJA | 3,513 |
| CECONY | Future Income Tax | |
| Income Taxes Disclosure [Line Items] | |
| Decrease in regulatory asset resulting from TCJA | 1,182 |
| CECONY | Revenue Taxes | |
| Income Taxes Disclosure [Line Items] | |
| Decrease in regulatory asset resulting from TCJA | $ 86 |
| X | ||||||||||
- Definition Income Taxes Disclosure [Line Items] No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Deferred Income Tax Liabilities, Net, Income Tax (Expense) Benefit No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Regulatory Assets, Income Tax Expense (Benefit) No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Regulatory Liabilities, Income Tax (Expense) Benefit No definition available.
|
| X | ||||||||||
- Definition Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Income Tax Expense (Benefit) No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies - Research and Development Costs (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Research and Development Expenses [Line Items] | |||
| Research and development costs | $ 24 | $ 24 | $ 23 |
| CECONY | |||
| Research and Development Expenses [Line Items] | |||
| Research and development costs | $ 23 | $ 22 | $ 22 |
| X | ||||||||||
- Definition Research and Development Expenses [Line Items] No definition available.
|
| X | ||||||||||
- Definition The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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Summary of Significant Accounting Policies - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Accounting Policies [Abstract] | |||
| Net income | $ 1,525 | $ 1,245 | $ 1,193 |
| Weighted average common shares outstanding – basic | 307.1 | 300.4 | 293.0 |
| Add: Incremental shares attributable to effect of potentially dilutive securities | 1.7 | 1.5 | 1.4 |
| Adjusted weighted average common shares outstanding – diluted | 308.8 | 301.9 | 294.4 |
| Net income per common share — basic (dollars per share) | $ 4.97 | $ 4.15 | $ 4.07 |
| Net income per common share — diluted (dollars per share) | $ 4.94 | $ 4.12 | $ 4.05 |
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of contingently issuable shares. Contingently issuable shares are those shares that are issuable for little or no cash contingent on certain conditions being met. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
Summary of Significant Accounting Policies - Changes in Accumulated Other Comprehensive Income/(Loss) by Component (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||
| BALANCE AS OF BEGINNING OF PERIOD | $ 14,306 | $ 13,061 | $ 12,585 |
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 7 | 11 |
| BALANCE AS OF END OF PERIOD | 15,425 | 14,306 | 13,061 |
| Accumulated OCI | |||
| AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||
| BALANCE AS OF BEGINNING OF PERIOD | (27) | (34) | (45) |
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 7 | 11 |
| BALANCE AS OF END OF PERIOD | (26) | (27) | (34) |
| Pension Plan Liabilities | |||
| AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||
| OCI before reclassifications, net of tax | (4) | 2 | 5 |
| Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax | 5 | 5 | 6 |
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 7 | 11 |
| OCI before reclassifications, tax | 3 | (1) | (3) |
| Amounts reclassified from accumulated OCI related to pension plan liabilities, tax | (3) | (3) | (4) |
| CECONY | |||
| AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 2 | 2 |
| CECONY | Accumulated OCI | |||
| AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||
| BALANCE AS OF BEGINNING OF PERIOD | (7) | (9) | (11) |
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 2 | 2 |
| BALANCE AS OF END OF PERIOD | (6) | (7) | (9) |
| CECONY | Pension Plan Liabilities | |||
| AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||
| OCI before reclassifications, net of tax | 0 | 1 | 1 |
| Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax | 1 | 1 | 1 |
| TOTAL OTHER COMPREHENSIVE INCOME, NET OF TAXES | 1 | 2 | 2 |
| OCI before reclassifications, tax | 1 | (1) | |
| Amounts reclassified from accumulated OCI related to pension plan liabilities, tax | $ (1) | $ (1) | $ (1) |
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Amount after tax, before reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of tax expense (benefit) allocated to other comprehensive income (loss) before reclassification adjustment from accumulated other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax of reclassification adjustments of other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Electric) (Details) - USD ($) |
1 Months Ended | 12 Months Ended | 36 Months Ended | |||||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2016 |
|
| Maximum | NYSPSC | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Percentage of total consolidated revenues | 15.00% | |||||||
| Percentage of debt to total consolidated debt | 20.00% | |||||||
| CECONY | Electric | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Amortization to income of net regulatory (assets) and liabilities | $ 123,000,000 | |||||||
| Retention of annual transmission congestion revenues | $ 90,000,000 | |||||||
| Actual earnings adjustment mechanism incentives | $ 13,000,000 | |||||||
| Deferred revenues | $ 101,000,000 | 45,000,000 | 101,000,000 | $ 98,000,000 | $ 146,000,000 | 101,000,000 | ||
| Negative revenue adjustments | 0 | 0 | 0 | 5,000,000 | ||||
| Cost reconciliations, deferred net regulatory liabilities | 68,000,000 | 35,000,000 | 68,000,000 | 26,000,000 | 57,000,000 | $ 68,000,000 | ||
| Net utility plant reconciliations | 400,000 | 9,000,000 | (17,000,000) | (6,000,000) | ||||
| Earnings sharing, threshold limit | $ 0 | 6,500,000 | 44,400,000 | $ 0 | ||||
| Earnings sharing, positive adjustment | 5,700,000 | |||||||
| Common equity ratio (percent) | 48.00% | |||||||
| Base rate change deferral regulatory liability impact | 0 | $ 0 | $ 30,000,000 | $ 0 | ||||
| Increase in gas base rate due to expiration of temporary credit under the prior rate plan | $ 48,000,000 | |||||||
| Deferrals for property taxes limitation from rates (percent) | 90.00% | |||||||
| Recovery deferral (percentage) | 80.00% | 80.00% | 80.00% | |||||
| Maximum deferral (percentage) | 30.00% | 30.00% | 30.00% | |||||
| CECONY | Electric | Deferred storm costs | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Amortization of regulatory asset | $ 107,000,000 | |||||||
| Decrease in recoverable property damage costs | 4,000,000 | |||||||
| CECONY | Electric | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Retention of annual transmission congestion revenues | $ 75,000,000 | |||||||
| Other earnings incentives | $ 5,000,000 | |||||||
| Authorized return on common equity (percent) | 9.00% | |||||||
| Actual return on common equity (percent) | 9.30% | |||||||
| Earnings sharing (percentage) | 9.50% | |||||||
| Common equity ratio (percent) | 48.00% | |||||||
| Recovery or refund of energy costs, deferral period | 10 years | |||||||
| CECONY | Electric | Scenario, Forecast | NYSPSC | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | $ 199,000,000 | |||||||
| CECONY | Electric | Year 1 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | $ (76,200,000) | $ (76,200,000) | (76,200,000) | |||||
| Amortization to income of net regulatory (assets) and liabilities | (37,000,000) | |||||||
| Average rate base | $ 17,323,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.05% | |||||||
| Authorized return on common equity (percent) | 9.20% | |||||||
| Actual return on common equity (percent) | 9.04% | |||||||
| Earnings sharing (percentage) | 9.80% | 9.80% | 9.80% | |||||
| Cost of long-term debt (percent) | 5.17% | 5.17% | 5.17% | |||||
| Deferral, annual maximum (not more than) (percent) | 0.05% | |||||||
| CECONY | Electric | Year 1 | Transmission and distribution | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 16,869,000,000 | |||||||
| CECONY | Electric | Year 1 | Storm hardening | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 89,000,000 | |||||||
| CECONY | Electric | Year 1 | Other | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 2,034,000,000 | |||||||
| CECONY | Electric | Year 1 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | 400,000,000 | |||||||
| CECONY | Electric | Year 1 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 195,000,000 | |||||||
| Amortization to income of net regulatory (assets) and liabilities | 84,000,000 | |||||||
| Potential earnings adjustment mechanism incentives | 28,000,000 | |||||||
| Potential penalties (annually) | 376,000,000 | |||||||
| Average rate base | $ 18,902,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 6.82% | |||||||
| Cost of long-term debt (percent) | 4.93% | |||||||
| Recovery of energy efficiency and savings program costs | $ 20,500,000 | |||||||
| CECONY | Electric | Year 1 | Scenario, Forecast | Electric average excluding AMI | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 21,689,000,000 | |||||||
| CECONY | Electric | Year 1 | Scenario, Forecast | Advanced metering infrastructure (AMI) | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 126,000,000 | |||||||
| CECONY | Electric | Year 2 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | $ 124,000,000 | $ 124,000,000 | 124,000,000 | |||||
| Amortization to income of net regulatory (assets) and liabilities | (37,000,000) | |||||||
| Retention of annual transmission congestion revenues | ||||||||
| Average rate base | $ 18,113,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.08% | |||||||
| Authorized return on common equity (percent) | 9.20% | |||||||
| Actual return on common equity (percent) | 10.16% | |||||||
| Earnings sharing (percentage) | 9.80% | 9.80% | 9.80% | |||||
| Cost of long-term debt (percent) | 5.23% | 5.23% | 5.23% | |||||
| Deferral, annual maximum (not more than) (percent) | 0.075% | |||||||
| CECONY | Electric | Year 2 | Transmission and distribution | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 17,401,000,000 | |||||||
| CECONY | Electric | Year 2 | Storm hardening | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 177,000,000 | |||||||
| CECONY | Electric | Year 2 | Other | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 2,102,000,000 | |||||||
| CECONY | Electric | Year 2 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | 400,000,000 | |||||||
| CECONY | Electric | Year 2 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 155,000,000 | |||||||
| Amortization to income of net regulatory (assets) and liabilities | 83,000,000 | |||||||
| Retention of annual transmission congestion revenues | ||||||||
| Potential earnings adjustment mechanism incentives | 47,000,000 | |||||||
| Potential penalties (annually) | 341,000,000 | |||||||
| Average rate base | $ 19,530,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 6.80% | |||||||
| Cost of long-term debt (percent) | 4.88% | |||||||
| Recovery of energy efficiency and savings program costs | $ 49,000,000 | |||||||
| CECONY | Electric | Year 2 | Scenario, Forecast | Electric average excluding AMI | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 22,338,000,000 | |||||||
| CECONY | Electric | Year 2 | Scenario, Forecast | Advanced metering infrastructure (AMI) | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 257,000,000 | |||||||
| CECONY | Electric | Year 3 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | $ 0 | $ 0 | 0 | |||||
| Amortization to income of net regulatory (assets) and liabilities | 123,000,000 | |||||||
| Retention of annual transmission congestion revenues | ||||||||
| Average rate base | $ 18,282,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 6.91% | |||||||
| Authorized return on common equity (percent) | 9.00% | |||||||
| Actual return on common equity (percent) | 9.66% | |||||||
| Earnings sharing (percentage) | 9.60% | 9.60% | 9.60% | |||||
| Cost of long-term debt (percent) | 5.09% | 5.09% | 5.09% | |||||
| Deferral, annual maximum (not more than) (percent) | 0.10% | |||||||
| CECONY | Electric | Year 3 | Transmission and distribution | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 17,929,000,000 | |||||||
| CECONY | Electric | Year 3 | Storm hardening | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 268,000,000 | |||||||
| CECONY | Electric | Year 3 | Other | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 2,069,000,000 | |||||||
| CECONY | Electric | Year 3 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | $ 400,000,000 | |||||||
| CECONY | Electric | Year 3 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 155,000,000 | |||||||
| Amortization to income of net regulatory (assets) and liabilities | 69,000,000 | |||||||
| Retention of annual transmission congestion revenues | ||||||||
| Potential earnings adjustment mechanism incentives | 64,000,000 | |||||||
| Potential penalties (annually) | 352,000,000 | |||||||
| Average rate base | $ 20,277,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 6.73% | |||||||
| Cost of long-term debt (percent) | 4.74% | |||||||
| Recovery of energy efficiency and savings program costs | $ 107,500,000 | |||||||
| CECONY | Electric | Year 3 | Scenario, Forecast | Electric average excluding AMI | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 23,002,000,000 | |||||||
| CECONY | Electric | Year 3 | Scenario, Forecast | Advanced metering infrastructure (AMI) | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 415,000,000 | |||||||
| X | ||||||||||
- Definition Average Net Utility Plant Rates No definition available.
|
| X | ||||||||||
- Definition Base rate change deferral regulatory liability impact. No definition available.
|
| X | ||||||||||
- Definition Common Equity Ratio Percentage No definition available.
|
| X | ||||||||||
- Definition Earnings Adjustment Mechanism, Incentive Revenue No definition available.
|
| X | ||||||||||
- Definition Impact On Earnings Had Lag Period Been Adjusted No definition available.
|
| X | ||||||||||
- Definition Other Incentive Revenue No definition available.
|
| X | ||||||||||
- Definition Potential Earnings Adjustment Mechanism Incentive Revenue No definition available.
|
| X | ||||||||||
- Definition Potential Penalty Expense No definition available.
|
| X | ||||||||||
- Definition Property Tax Deferrals, Limitation From Rate No definition available.
|
| X | ||||||||||
- Definition Property Tax Deferrals Limitation From Rate, Annual Maximum No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Additional Rate Increase (Decrease), Amount No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Energy and Efficiency Savings Program, Recovery Costs No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Maximum Deferral Percentage No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Notification Threshold for Debt Capital Structure, Percentage No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Notification Threshold for Non-Utility Investments, Percentage No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Property, Plant and Equipment, Rate Base Adjustments No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Recovery Costs, Deferral Period Two No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Recovery Deferral Percentage No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Return on Equity, Percentage No definition available.
|
| X | ||||||||||
- Definition Regulatory Matters Average Base Rate No definition available.
|
| X | ||||||||||
- Definition Retention Of Annual Transmission Congestion Revenues No definition available.
|
| X | ||||||||||
- Definition Revenue Requirement Earnings Percentage No definition available.
|
| X | ||||||||||
- Definition Revenue Sharing, Adjustment No definition available.
|
| X | ||||||||||
- Definition Revenue Sharing Threshold Limit No definition available.
|
| X | ||||||||||
- Definition Weighted Average Cost Of Capital No definition available.
|
| X | ||||||||||
- Definition The expense charged against earnings during the period to allocate the capitalized costs of regulatory assets over the periods expected to benefit from such costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from regulatory assets and liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the public utility damage costs that will be permitted by regulatory agencies to be recovered from rate payers. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of public utility's approved return on equity. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of operating expense for depreciation and amortization of regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Gas) (Details) - CECONY - Gas - USD ($) |
1 Months Ended | 12 Months Ended | 36 Months Ended | |||||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2016 |
|
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Amortization to income of net regulatory (assets) and liabilities | $ 4,000,000 | |||||||
| Regulatory liabilities, amortization period | 3 years | |||||||
| Amount of revenues retained | $ 65,000,000 | $ 65,000,000 | $ 66,000,000 | $ 70,000,000 | $ 65,000,000 | |||
| Percentage of revenue reserve | 15.00% | |||||||
| Deferred revenues | 71,000,000 | $ 3,000,000 | 71,000,000 | 54,000,000 | 28,000,000 | $ 71,000,000 | ||
| Negative revenue adjustments | 5,000,000 | 0 | 0 | 0 | ||||
| Cost reconciliations, deferred net regulatory liabilities | $ 32,000,000 | 2,000,000 | 32,000,000 | 11,000,000 | 38,000,000 | $ 32,000,000 | ||
| Net utility plant reconciliations | $ 2,200,000 | $ 0 | 1,000,000 | 0 | ||||
| Earnings sharing (percentage) | 9.90% | 9.90% | 9.90% | |||||
| Earnings sharing, threshold limit | $ 0 | 0 | 0 | |||||
| Common equity ratio (percent) | 48.00% | |||||||
| Base rate change deferral regulatory liability impact | $ 32,000,000 | 32,000,000 | $ 32,000,000 | |||||
| Increase in gas base rate due to expiration of temporary credit under the prior rate plan | 41,000,000 | |||||||
| Difference in property taxes (percent) | 90.00% | |||||||
| Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Amount of revenues retained | $ 65,000,000 | 65,000,000 | $ 65,000,000 | |||||
| Potential penalties (annually) | $ 56,000,000 | $ 44,000,000 | $ 33,000,000 | |||||
| Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Percentage of revenue reserve | 15.00% | |||||||
| Other earnings incentives | $ 7,000,000 | |||||||
| Earnings sharing (percentage) | 9.50% | |||||||
| Common equity ratio (percent) | 48.00% | |||||||
| Deferral, annual maximum (not more than) (percent) | 0.10% | |||||||
| Scenario, Forecast | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Amount of revenues retained | $ 65,000,000 | |||||||
| Year 1 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | (54,600,000) | |||||||
| Average rate base | $ 3,521,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.10% | |||||||
| Authorized return on common equity (percent) | 9.30% | |||||||
| Actual return on common equity (percent) | 8.02% | |||||||
| Cost of long-term debt (percent) | 5.17% | 5.17% | 5.17% | |||||
| Year 1 | Gas delivery | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 3,899,000,000 | |||||||
| Year 1 | Storm hardening | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 3,000,000 | |||||||
| Year 1 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | (5,000,000) | |||||||
| Amortization to income of net regulatory (assets) and liabilities | 39,000,000 | |||||||
| Potential incentives if performance targets are met | 7,000,000 | |||||||
| Potential penalties (annually) | 68,000,000 | |||||||
| Average rate base | $ 4,841,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 6.82% | |||||||
| Authorized return on common equity (percent) | 9.00% | |||||||
| Actual return on common equity (percent) | 9.22% | |||||||
| Cost of long-term debt (percent) | 4.93% | |||||||
| Year 1 | Scenario, Forecast | Gas average excluding AMI | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 5,844,000,000 | |||||||
| Year 1 | Scenario, Forecast | Advanced metering infrastructure (AMI) | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 27,000,000 | |||||||
| Year 2 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 38,600,000 | |||||||
| Average rate base | $ 3,863,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.13% | |||||||
| Actual return on common equity (percent) | 8.13% | |||||||
| Cost of long-term debt (percent) | 5.23% | 5.23% | 5.23% | |||||
| Year 2 | Gas delivery | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 4,258,000,000 | |||||||
| Year 2 | Storm hardening | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 8,000,000 | |||||||
| Year 2 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 92,000,000 | |||||||
| Amortization to income of net regulatory (assets) and liabilities | 37,000,000 | |||||||
| Potential incentives if performance targets are met | 8,000,000 | |||||||
| Potential penalties (annually) | 63,000,000 | |||||||
| Average rate base | $ 5,395,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 6.80% | |||||||
| Cost of long-term debt (percent) | 4.88% | |||||||
| Year 2 | Scenario, Forecast | Gas average excluding AMI | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 6,512,000,000 | |||||||
| Year 2 | Scenario, Forecast | Advanced metering infrastructure (AMI) | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | 57,000,000 | |||||||
| Year 3 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 56,800,000 | |||||||
| Average rate base | $ 4,236,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.21% | |||||||
| Actual return on common equity (percent) | 7.83% | |||||||
| Cost of long-term debt (percent) | 5.39% | 5.39% | 5.39% | |||||
| Year 3 | Gas delivery | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 4,698,000,000 | |||||||
| Year 3 | Storm hardening | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 30,000,000 | |||||||
| Year 3 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 90,000,000 | |||||||
| Amortization to income of net regulatory (assets) and liabilities | 36,000,000 | |||||||
| Potential incentives if performance targets are met | 8,000,000 | |||||||
| Potential penalties (annually) | 70,000,000 | |||||||
| Average rate base | $ 6,005,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 6.73% | |||||||
| Cost of long-term debt (percent) | 4.74% | |||||||
| Year 3 | Scenario, Forecast | Gas average excluding AMI | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 7,177,000,000 | |||||||
| Year 3 | Scenario, Forecast | Advanced metering infrastructure (AMI) | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Net utility plant reconciliations | $ 100,000,000 | |||||||
| X | ||||||||||
- Definition Average Net Utility Plant Rates No definition available.
|
| X | ||||||||||
- Definition Base rate change deferral regulatory liability impact. No definition available.
|
| X | ||||||||||
- Definition Base rate increase decrease. No definition available.
|
| X | ||||||||||
- Definition Common Equity Ratio Percentage No definition available.
|
| X | ||||||||||
- Definition Impact On Earnings Had Lag Period Been Adjusted No definition available.
|
| X | ||||||||||
- Definition Other Incentive Revenue No definition available.
|
| X | ||||||||||
- Definition Percentage of Revenue Reserve No definition available.
|
| X | ||||||||||
- Definition Potential Earnings Adjustment Mechanism Incentive Revenue No definition available.
|
| X | ||||||||||
- Definition Potential Penalty Expense No definition available.
|
| X | ||||||||||
- Definition Property Tax Deferrals Limitation From Rate, Annual Maximum No definition available.
|
| X | ||||||||||
- Definition Property Tax Deferrals Rate Difference No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Additional Rate Increase (Decrease), Amount No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Return on Equity, Percentage No definition available.
|
| X | ||||||||||
- Definition Regulatory Matters Average Base Rate No definition available.
|
| X | ||||||||||
- Definition Revenue Requirement Earnings Percentage No definition available.
|
| X | ||||||||||
- Definition Revenue Sharing Threshold Limit No definition available.
|
| X | ||||||||||
- Definition Weighted Average Cost Of Capital No definition available.
|
| X | ||||||||||
- Definition Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from regulatory assets and liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of public utility's approved return on equity. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amortization period for the recovery of regulatory liability, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
|
| X | ||||||||||
- Definition A segregation of retained earnings which is unavailable for dividend distribution. Includes also retained earnings appropriated for loss contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of operating expense for depreciation and amortization of regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Steam) (Details) - CECONY - Steam - USD ($) |
12 Months Ended | 36 Months Ended | |||
|---|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2016 |
|
| Public Utilities, General Disclosures [Line Items] | |||||
| Amortization to income of net regulatory (assets) and liabilities | $ 37,000,000 | ||||
| Regulatory liabilities, amortization period | 3 years | ||||
| Negative revenue adjustments | $ 0 | $ 0 | $ 0 | $ 0 | |
| Cost reconciliation, deferred net regulatory liabilities | 14,000,000 | 8,000,000 | 42,000,000 | $ 8,000,000 | |
| Cost reconciliations | 17,000,000 | ||||
| Net utility plant reconciliations | 0 | $ 0 | 0 | $ 100,000 | |
| Authorized return on common equity (percent) | 9.30% | ||||
| Earnings sharing (percentage) | 9.90% | 9.90% | |||
| Earnings sharing, threshold limit | $ 8,500,000 | $ 7,800,000 | $ 11,500,000 | ||
| Earnings sharing, positive adjustment | 4,000,000 | ||||
| Common equity ratio (percent) | 48.00% | ||||
| Other regulatory liabilities | $ 8,000,000 | $ 8,000,000 | |||
| Difference in property taxes (percent) | 90.00% | ||||
| Deferral, annual maximum (not more than) (percent) | 0.10% | ||||
| Year 1 | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Base rate changes | $ (22,400,000) | ||||
| Average rate base | $ 1,511,000,000 | ||||
| Weighted average cost of capital (after-tax) (percent) | 7.10% | ||||
| Actual return on common equity (percent) | 9.82% | ||||
| Cost of long-term debt (percent) | 5.17% | 5.17% | |||
| Year 1 | Production | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Net utility plant reconciliations | $ 1,752,000,000 | ||||
| Year 1 | Distribution | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Net utility plant reconciliations | 6,000,000 | ||||
| Year 1 | Maximum | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Potential penalties (annually) | 1,000,000 | ||||
| Year 2 | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Base rate changes | 19,800,000 | ||||
| Average rate base | $ 1,547,000,000 | ||||
| Weighted average cost of capital (after-tax) (percent) | 7.13% | ||||
| Actual return on common equity (percent) | 10.88% | ||||
| Cost of long-term debt (percent) | 5.23% | 5.23% | |||
| Year 2 | Production | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Net utility plant reconciliations | $ 1,732,000,000 | ||||
| Year 2 | Distribution | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Net utility plant reconciliations | 11,000,000 | ||||
| Year 2 | Maximum | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Potential penalties (annually) | 1,000,000 | ||||
| Year 3 | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Base rate changes | 20,300,000 | ||||
| Average rate base | $ 1,604,000,000 | ||||
| Weighted average cost of capital (after-tax) (percent) | 7.21% | ||||
| Actual return on common equity (percent) | 10.54% | ||||
| Cost of long-term debt (percent) | 5.39% | 5.39% | |||
| Year 3 | Production | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Net utility plant reconciliations | $ 1,720,000,000 | ||||
| Year 3 | Distribution | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Net utility plant reconciliations | 25,000,000 | ||||
| Year 3 | Maximum | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Potential penalties (annually) | 1,000,000 | ||||
| Year 4 | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Base rate changes | $ 0 | ||||
| Actual return on common equity (percent) | 9.51% | ||||
| X | ||||||||||
- Definition Average Net Utility Plant Rates No definition available.
|
| X | ||||||||||
- Definition Base rate increase decrease. No definition available.
|
| X | ||||||||||
- Definition Common Equity Ratio Percentage No definition available.
|
| X | ||||||||||
- Definition Impact On Earnings Had Lag Period Been Adjusted No definition available.
|
| X | ||||||||||
- Definition Other Regulatory Liabilities No definition available.
|
| X | ||||||||||
- Definition Potential Penalty Expense No definition available.
|
| X | ||||||||||
- Definition Property Tax Deferrals Limitation From Rate, Annual Maximum No definition available.
|
| X | ||||||||||
- Definition Property Tax Deferrals Rate Difference No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Return on Equity, Percentage No definition available.
|
| X | ||||||||||
- Definition Regulatory Matters Average Base Rate No definition available.
|
| X | ||||||||||
- Definition Revenue Requirement Earnings Percentage No definition available.
|
| X | ||||||||||
- Definition Revenue Sharing, Adjustment No definition available.
|
| X | ||||||||||
- Definition Revenue Sharing Threshold Limit No definition available.
|
| X | ||||||||||
- Definition Weighted Average Cost Of Capital No definition available.
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences derived regulatory assets and liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from regulatory assets and liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of public utility's approved return on equity. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amortization period for the recovery of regulatory liability, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
|
| X | ||||||||||
- Definition Amount of operating expense for depreciation and amortization of regulated operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Regulatory Matters - Summary of Utilities Rate Plans (O&R New York-Electric) (Details) - O&R - Electric - USD ($) |
12 Months Ended | 24 Months Ended | 40 Months Ended | |||||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
Dec. 31, 2012 |
Oct. 31, 2017 |
Oct. 31, 2015 |
|
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Deferred revenues | $ 11,200,000 | $ 6,300,000 | $ 0 | $ (3,400,000) | $ 3,200,000 | $ 2,600,000 | ||
| Negative revenue adjustments | 0 | 0 | 1,250,000 | 0 | 0 | 0 | ||
| Deferral of net increase (decrease) to regulatory assets | 3,200,000 | 7,400,000 | 300,000 | (200,000) | 4,100,000 | 7,800,000 | ||
| Net utility plant reconciliations | (1,900,000) | (1,900,000) | $ 2,200,000 | (2,300,000) | $ (1,100,000) | $ 4,200,000 | ||
| Authorized return on common equity (percent) | 9.00% | |||||||
| Earnings sharing (percentage) | 9.60% | |||||||
| Earnings sharing, threshold limit | $ 300,000 | $ 6,100,000 | $ 1,000,000 | |||||
| Common equity ratio (percent) | 48.00% | 48.00% | ||||||
| Deferred storm and property reserve deficiency, noncurrent | $ 59,300,000 | |||||||
| Deferred storm and property reserve deficiency, recovery period | 5 years | |||||||
| Deferred storm and property reserve deficiency not recovered | $ 1,000,000 | |||||||
| Property Tax and Interest Rate Reconciliations | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory assets not recoverable | 4,000,000 | |||||||
| Year 1 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 9,300,000 | $ 19,400,000 | ||||||
| Amortization to income of net regulatory assets | (8,500,000) | (32,200,000) | ||||||
| Net utility plant reconciliations | 928,000,000 | 678,000,000 | ||||||
| Average rate base | $ 763,000,000 | $ 671,000,000 | ||||||
| Weighted average cost of capital (after-tax) (percent) | 7.10% | 7.61% | ||||||
| Authorized return on common equity (percent) | 9.40% | |||||||
| Actual return on common equity (percent) | 10.80% | 12.90% | ||||||
| Cost of long-term debt (percent) | 5.42% | 6.07% | ||||||
| Deferred storm and property reserve deficiency, noncurrent | $ 11,850,000 | |||||||
| Rate exclusion amount with balance below regulatory threshold | 1,000,000 | |||||||
| Year 1 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | 4,000,000 | $ 3,000,000 | ||||||
| Year 2 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 8,800,000 | $ 8,800,000 | ||||||
| Amortization to income of net regulatory assets | (9,400,000) | |||||||
| Regulatory assets, amortization period | 3 years | |||||||
| Net utility plant reconciliations | 970,000,000 | $ 704,000,000 | ||||||
| Average rate base | $ 805,000,000 | $ 708,000,000 | ||||||
| Weighted average cost of capital (after-tax) (percent) | 7.06% | 7.65% | ||||||
| Authorized return on common equity (percent) | 9.50% | |||||||
| Actual return on common equity (percent) | 9.70% | 8.70% | ||||||
| Cost of long-term debt (percent) | 5.35% | 6.07% | ||||||
| Deferred storm and property reserve deficiency, noncurrent | $ 11,850,000 | |||||||
| Rate exclusion amount with balance below regulatory threshold | 9,000,000 | |||||||
| Year 2 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | 4,000,000 | $ 3,000,000 | ||||||
| Year 3 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 15,200,000 | |||||||
| Net utility plant reconciliations | 753,000,000 | |||||||
| Average rate base | $ 759,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.48% | |||||||
| Authorized return on common equity (percent) | 9.60% | |||||||
| Actual return on common equity (percent) | 9.40% | |||||||
| Cost of long-term debt (percent) | 5.64% | |||||||
| Year 3 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | $ 4,000,000 | $ 3,000,000 | ||||||
| X | ||||||||||
- Definition Average Net Utility Plant Rates No definition available.
|
| X | ||||||||||
- Definition Base rate increase decrease. No definition available.
|
| X | ||||||||||
- Definition Common Equity Ratio Percentage No definition available.
|
| X | ||||||||||
- Definition Deferred Expense Recognized No definition available.
|
| X | ||||||||||
- Definition Deferred Storm and Property Reserve Deficiency Not Recovered No definition available.
|
| X | ||||||||||
- Definition Deferred Storm and Property Reserve Deficiency, Recovery Period No definition available.
|
| X | ||||||||||
- Definition Impact On Earnings Had Lag Period Been Adjusted No definition available.
|
| X | ||||||||||
- Definition Percentage Of Debt Securities Amortized Cost Based No definition available.
|
| X | ||||||||||
- Definition Potential Penalty Expense No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Return on Equity, Percentage No definition available.
|
| X | ||||||||||
- Definition Rate Exclusion Amount with Balance Below Regulatory Threshold No definition available.
|
| X | ||||||||||
- Definition Regulatory Assets Not Recoverable No definition available.
|
| X | ||||||||||
- Definition Regulatory Matters Average Base Rate No definition available.
|
| X | ||||||||||
- Definition Revenue Requirement Earnings Percentage No definition available.
|
| X | ||||||||||
- Definition Revenue Sharing Threshold Limit No definition available.
|
| X | ||||||||||
- Definition Weighted Average Cost Of Capital No definition available.
|
| X | ||||||||||
- Definition The expense charged against earnings during the period to allocate the capitalized costs of regulatory assets over the periods expected to benefit from such costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of capitalized storm costs of a regulated entity that are expected to be recoverable through rate adjustments after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of public utility's approved return on equity. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Regulatory Matters - Summary of Utilities Rate Plans (O&R New York-Gas) (Details) - O&R - Gas - USD ($) |
12 Months Ended | 36 Months Ended | 72 Months Ended | |||||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
Dec. 31, 2012 |
Oct. 31, 2018 |
Oct. 31, 2015 |
|
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Amortization to income of net regulatory assets | $ (2,000,000) | |||||||
| Regulatory assets, amortization period | 3 years | |||||||
| Deferred revenues | $ 1,700,000 | $ 6,200,000 | $ (800,000) | $ (100,000) | $ 700,000 | $ 4,700,000 | ||
| Negative revenue adjustments | 0 | 0 | 0 | 0 | 0 | 0 | ||
| Cost reconciliations | (3,500,000) | 6,600,000 | (4,500,000) | 8,300,000 | 8,300,000 | 700,000 | ||
| Net utility plant reconciliations | 0 | 0 | 0 | 0 | 0 | 700,000 | ||
| Weighted average cost of capital (after-tax) (percent) | 8.49% | |||||||
| Authorized return on common equity (percent) | 10.40% | |||||||
| Earnings sharing, threshold limit | $ 200,000 | $ 4,000,000 | $ 0 | $ 0 | $ 0 | $ 0 | ||
| Cost of long-term debt (percent) | 6.81% | |||||||
| Common equity ratio (percent) | 48.00% | |||||||
| Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Authorized return on common equity (percent) | 9.00% | |||||||
| Earnings sharing (percentage) | 9.60% | |||||||
| Common equity ratio (percent) | 48.00% | |||||||
| Scenario, Forecast | Property Tax and Interest Rate Reconciliations | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory assets not recoverable | $ 14,000,000 | |||||||
| Year 1 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | $ 9,000,000 | |||||||
| Average rate base | $ 280,000,000 | |||||||
| Actual return on common equity (percent) | 10.20% | |||||||
| Earnings sharing (percentage) | 11.40% | |||||||
| Year 1 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | $ 1,400,000 | |||||||
| Year 1 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 16,400,000 | |||||||
| Amortization to income of net regulatory assets | (1,700,000) | |||||||
| Net utility plant reconciliations | 492,000,000 | |||||||
| Average rate base | $ 366,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.10% | |||||||
| Actual return on common equity (percent) | 11.20% | |||||||
| Cost of long-term debt (percent) | 5.42% | |||||||
| Rate exclusion amount with balance below regulatory threshold | $ 500,000 | |||||||
| Year 1 | Scenario, Forecast | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | 3,700,000 | |||||||
| Year 2 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 9,000,000 | |||||||
| Average rate base | $ 296,000,000 | |||||||
| Actual return on common equity (percent) | 9.60% | |||||||
| Year 2 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | $ 1,400,000 | |||||||
| Year 2 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 16,400,000 | |||||||
| Amortization to income of net regulatory assets | (2,100,000) | |||||||
| Net utility plant reconciliations | 518,000,000 | |||||||
| Average rate base | $ 391,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.06% | |||||||
| Actual return on common equity (percent) | 9.70% | |||||||
| Cost of long-term debt (percent) | 5.35% | |||||||
| Rate exclusion amount with balance below regulatory threshold | $ 4,200,000 | |||||||
| Year 2 | Scenario, Forecast | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | 4,700,000 | |||||||
| Year 3 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 4,600,000 | |||||||
| Base rate change through surcharge | 4,300,000 | |||||||
| Average rate base | $ 309,000,000 | |||||||
| Actual return on common equity (percent) | 12.60% | |||||||
| Year 3 | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | $ 1,400,000 | |||||||
| Year 3 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | 5,800,000 | |||||||
| Amortization to income of net regulatory assets | (2,500,000) | |||||||
| Net utility plant reconciliations | 546,000,000 | |||||||
| Average rate base | $ 417,000,000 | |||||||
| Weighted average cost of capital (after-tax) (percent) | 7.06% | |||||||
| Cost of long-term debt (percent) | 5.35% | |||||||
| Rate exclusion amount with balance below regulatory threshold | $ 7,200,000 | |||||||
| Year 3 | Scenario, Forecast | Maximum | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Potential penalties (annually) | 4,900,000 | |||||||
| Year 4 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | $ 0 | |||||||
| Actual return on common equity (percent) | 10.20% | |||||||
| Year 4 | Scenario, Forecast | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate change through surcharge | $ 10,600,000 | |||||||
| Year 5 | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Base rate changes | $ 0 | |||||||
| Actual return on common equity (percent) | 6.10% | |||||||
| X | ||||||||||
- Definition Average Net Utility Plant Rates No definition available.
|
| X | ||||||||||
- Definition Base rate change through surcharge. No definition available.
|
| X | ||||||||||
- Definition Base rate increase decrease. No definition available.
|
| X | ||||||||||
- Definition Common Equity Ratio Percentage No definition available.
|
| X | ||||||||||
- Definition Impact On Earnings Had Lag Period Been Adjusted No definition available.
|
| X | ||||||||||
- Definition Percentage Of Debt Securities Amortized Cost Based No definition available.
|
| X | ||||||||||
- Definition Potential Penalty Expense No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Return on Equity, Percentage No definition available.
|
| X | ||||||||||
- Definition Rate Exclusion Amount with Balance Below Regulatory Threshold No definition available.
|
| X | ||||||||||
- Definition Regulatory Assets Not Recoverable No definition available.
|
| X | ||||||||||
- Definition Regulatory Matters Average Base Rate No definition available.
|
| X | ||||||||||
- Definition Revenue Requirement Earnings Percentage No definition available.
|
| X | ||||||||||
- Definition Revenue Sharing Threshold Limit No definition available.
|
| X | ||||||||||
- Definition Weighted Average Cost Of Capital No definition available.
|
| X | ||||||||||
- Definition The expense charged against earnings during the period to allocate the capitalized costs of regulatory assets over the periods expected to benefit from such costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences derived regulatory assets and liabilities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of public utility's approved return on equity. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Regulatory Matters - Summary of Utilities Rate Plans (RECO) (Details) - RECO - USD ($) $ in Millions |
1 Months Ended | 12 Months Ended | 31 Months Ended |
|---|---|---|---|
Mar. 31, 2017 |
Dec. 31, 2017 |
Feb. 28, 2017 |
|
| Public Utilities, General Disclosures [Line Items] | |||
| Amortization to income of net regulatory (assets) and liabilities | $ 0.2 | $ 0.4 | |
| Regulatory liabilities, amortization period | 3 years | 3 years | |
| Amortization to income of net regulatory assets | $ (25.6) | $ (25.6) | |
| Regulatory assets, amortization period | 4 years | 4 years | |
| Average rate base | $ 178.7 | $ 172.2 | |
| Weighted average cost of capital (after-tax) (percent) | 7.47% | 7.83% | |
| Authorized return on common equity (percent) | 9.60% | 9.75% | |
| Cost of long-term debt (percent) | 5.37% | 5.89% | |
| Common equity ratio (percent) | 49.70% | 50.00% | |
| Electric | |||
| Public Utilities, General Disclosures [Line Items] | |||
| Plan electric system storm hardening amount | $ 15.7 | ||
| Plan period (years) | 3 years | ||
| Year 1 | |||
| Public Utilities, General Disclosures [Line Items] | |||
| Base rate changes | $ 1.7 | $ 13.0 | |
| Actual return on common equity (percent) | 9.20% | ||
| Year 2 | |||
| Public Utilities, General Disclosures [Line Items] | |||
| Actual return on common equity (percent) | 8.70% |
| X | ||||||||||
- Definition Base rate increase decrease. No definition available.
|
| X | ||||||||||
- Definition Common Equity Ratio Percentage No definition available.
|
| X | ||||||||||
- Definition Percentage Of Debt Securities Amortized Cost Based No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Plan Amount No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Plan Period No definition available.
|
| X | ||||||||||
- Definition Public Utilities, Return on Equity, Percentage No definition available.
|
| X | ||||||||||
- Definition Regulatory Matters Average Base Rate No definition available.
|
| X | ||||||||||
- Definition Weighted Average Cost Of Capital No definition available.
|
| X | ||||||||||
- Definition The expense charged against earnings during the period to allocate the capitalized costs of regulatory assets over the periods expected to benefit from such costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of public utility's approved return on equity. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
|
| X | ||||||||||
- Definition Amortization period for the recovery of regulatory liability, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
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Regulatory Matters - Additional Information (Details) - USD ($) $ in Millions |
1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|---|---|
Jan. 31, 2019 |
Jan. 31, 2018 |
Apr. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2017 |
Dec. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2016 |
|
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory assets | $ 4,333.0 | $ 4,333.0 | $ 7,124.0 | |||||
| Decrease in net deferred tax liabilities resulting from TCJA | 5,312.0 | |||||||
| Regulatory liabilities | 4,577.0 | 4,577.0 | 1,905.0 | |||||
| Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Increase in regulatory liability resulting from TCJA | 3,713.0 | |||||||
| Regulatory liabilities | 2,545.0 | 2,545.0 | 0.0 | |||||
| Net Unbilled Revenue Deferrals | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory liabilities | $ 183.0 | 183.0 | 145.0 | |||||
| Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 1,250.0 | |||||||
| Revenue Taxes | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 90.0 | |||||||
| O&R | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in net deferred tax liabilities resulting from TCJA | 216.0 | |||||||
| O&R | Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Increase in regulatory liability resulting from TCJA | 161.0 | |||||||
| O&R | Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 51.0 | |||||||
| O&R | Revenue Taxes | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 4.0 | |||||||
| O&R | NYSPSC | Subsequent Event | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Requested rate increase, amount | $ 4.5 | |||||||
| Requested return on equity (percent) | 9.75% | |||||||
| Requested equity capital structure (percent) | 48.00% | |||||||
| O&R | NYSPSC | Electric | Subsequent Event | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Requested rate increase, amount | $ 20.3 | |||||||
| Requested return on equity (percent) | 9.75% | |||||||
| Requested equity capital structure (percent) | 48.00% | |||||||
| RECO | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in net deferred tax liabilities resulting from TCJA | 45.0 | |||||||
| RECO | Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Increase in regulatory liability resulting from TCJA | 28.0 | |||||||
| RECO | Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 17.0 | |||||||
| RECO | Revenue Taxes | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 0.0 | |||||||
| RECO | FERC | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Requested rate increase, amount | $ 17.7 | $ 11.8 | ||||||
| Requested return on equity (percent) | 10.00% | |||||||
| CECONY | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory assets | $ 3,925.0 | 3,925.0 | 6,563.0 | |||||
| Decrease in net deferred tax liabilities resulting from TCJA | 4,781.0 | |||||||
| Regulatory liabilities | 4,219.0 | 4,219.0 | 1,712.0 | |||||
| CECONY | Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Increase in regulatory liability resulting from TCJA | 3,513.0 | |||||||
| Regulatory liabilities | 2,390.0 | 2,390.0 | 0.0 | |||||
| CECONY | Net Unbilled Revenue Deferrals | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory liabilities | 183.0 | 183.0 | $ 145.0 | |||||
| CECONY | Future Income Tax | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 1,182.0 | |||||||
| CECONY | Revenue Taxes | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Decrease in regulatory asset resulting from TCJA | 86.0 | |||||||
| CECONY | NYSPSC | Issued by NYSPSC on MTA Subway Power Outage | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory costs | 65.0 | 65.0 | ||||||
| Regulatory assets | 50.0 | 50.0 | ||||||
| CECONY | NYSPSC | Scenario, Forecast | Issued by NYSPSC on MTA Subway Power Outage | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory costs | $ 137.0 | |||||||
| Regulatory assets | 127.0 | |||||||
| CECONY | NYSPSC | Electric | Issued by NYSPSC on MTA Subway Power Outage | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory costs | $ 15.0 | $ 15.0 | ||||||
| CECONY | NYSPSC | Electric | Scenario, Forecast | Issued by NYSPSC on MTA Subway Power Outage | ||||||||
| Public Utilities, General Disclosures [Line Items] | ||||||||
| Regulatory costs | $ 10.0 | |||||||
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Deferred Income Tax Liabilities, Net, Income Tax (Expense) Benefit No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Regulatory Assets, Income Tax Expense (Benefit) No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Regulatory Liabilities, Income Tax (Expense) Benefit No definition available.
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- Definition Amount of regulatory costs not yet approved by the regulatory authority. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | $ 4,266 | $ 7,024 |
| Regulatory assets – current | 67 | 100 |
| Total Regulatory Assets | 4,333 | 7,124 |
| Unrecognized pension and other postretirement costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 2,526 | 2,874 |
| Future income tax | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 0 | 2,439 |
| Environmental remediation costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 793 | 823 |
| Revenue taxes | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 260 | 295 |
| Pension and other postretirement benefits deferrals | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 79 | 38 |
| Recoverable energy costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 60 | 42 |
| Regulatory assets – current | 27 | 9 |
| Municipal infrastructure support costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 56 | 44 |
| Property tax reconciliation | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 51 | 37 |
| MTA power reliability deferral | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 50 | 0 |
| Deferred derivative losses | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 44 | 48 |
| Deferred storm costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 38 | 56 |
| Brooklyn Queens demand management program | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 37 | 29 |
| Unamortized loss on reacquired debt | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 37 | 43 |
| Indian Point Energy Center program costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 29 | 50 |
| Preferred stock redemption | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 24 | 25 |
| Workers’ compensation | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 10 | 13 |
| Net electric deferrals | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 9 | 24 |
| O&R transition bond charges | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 9 | 15 |
| Surcharge for New York State assessment | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 2 | 28 |
| Other | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 152 | 101 |
| Deferred derivative losses | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – current | 40 | 91 |
| CECONY | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 3,863 | 6,473 |
| Regulatory assets – current | 62 | 90 |
| Total Regulatory Assets | 3,925 | 6,563 |
| CECONY | Unrecognized pension and other postretirement costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 2,376 | 2,730 |
| CECONY | Future income tax | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 0 | 2,325 |
| CECONY | Environmental remediation costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 677 | 711 |
| CECONY | Revenue taxes | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 248 | 280 |
| CECONY | Pension and other postretirement benefits deferrals | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 58 | 7 |
| CECONY | Recoverable energy costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 52 | 38 |
| Regulatory assets – current | 25 | 4 |
| CECONY | Municipal infrastructure support costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 56 | 44 |
| CECONY | Property tax reconciliation | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 25 | 0 |
| CECONY | MTA power reliability deferral | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 50 | 0 |
| CECONY | Deferred derivative losses | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 37 | 42 |
| CECONY | Deferred storm costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 0 | 3 |
| CECONY | Brooklyn Queens demand management program | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 37 | 29 |
| CECONY | Unamortized loss on reacquired debt | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 35 | 41 |
| CECONY | Indian Point Energy Center program costs | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 29 | 50 |
| CECONY | Preferred stock redemption | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 24 | 25 |
| CECONY | Workers’ compensation | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 10 | 13 |
| CECONY | Net electric deferrals | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 9 | 24 |
| CECONY | O&R transition bond charges | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 0 | 0 |
| CECONY | Surcharge for New York State assessment | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 2 | 26 |
| CECONY | Other | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – noncurrent | 138 | 85 |
| CECONY | Deferred derivative losses | ||
| Regulatory Assets [Line Items] | ||
| Regulatory assets – current | $ 37 | $ 86 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Regulatory Matters - Regulatory Liabilities (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | $ 4,577 | $ 1,905 |
| Regulatory liabilities—current | 101 | 128 |
| Total Regulatory Liabilities | 4,678 | 2,033 |
| Future income tax | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 2,545 | 0 |
| Allowance for cost of removal less salvage | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 846 | 755 |
| Pension and other postretirement benefit deferrals | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 207 | 193 |
| Net unbilled revenue deferrals | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 183 | 145 |
| Energy efficiency portfolio standard unencumbered funds | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 127 | 0 |
| Property tax reconciliation | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 107 | 178 |
| Unrecognized other postretirement costs | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 92 | 60 |
| Settlement of prudence proceeding | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 66 | 95 |
| Property tax refunds | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 44 | 1 |
| Carrying charges on repair allowance and bonus depreciation | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 43 | 68 |
| New York State income tax rate change | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 36 | 61 |
| Variable-rate tax-exempt debt - cost rate reconciliation | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 30 | 55 |
| Earnings sharing - electric, gas and steam | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 29 | 39 |
| Settlement of gas proceedings | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 27 | 27 |
| Base rate change deferrals | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 21 | 40 |
| Net utility plant reconciliations | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 12 | 16 |
| Other | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 162 | 172 |
| Refundable energy costs | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities—current | 41 | 29 |
| Deferred derivative gains | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities—current | 31 | 28 |
| Revenue decoupling mechanism | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities—current | 29 | 71 |
| CECONY | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 4,219 | 1,712 |
| Regulatory liabilities—current | 65 | 90 |
| Total Regulatory Liabilities | 4,284 | 1,802 |
| CECONY | Future income tax | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 2,390 | 0 |
| CECONY | Allowance for cost of removal less salvage | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 719 | 641 |
| CECONY | Pension and other postretirement benefit deferrals | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 181 | 162 |
| CECONY | Net unbilled revenue deferrals | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 183 | 145 |
| CECONY | Energy efficiency portfolio standard unencumbered funds | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 122 | 0 |
| CECONY | Property tax reconciliation | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 107 | 178 |
| CECONY | Unrecognized other postretirement costs | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 92 | 60 |
| CECONY | Settlement of prudence proceeding | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 66 | 95 |
| CECONY | Property tax refunds | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 44 | 1 |
| CECONY | Carrying charges on repair allowance and bonus depreciation | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 42 | 67 |
| CECONY | New York State income tax rate change | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 35 | 60 |
| CECONY | Variable-rate tax-exempt debt - cost rate reconciliation | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 26 | 48 |
| CECONY | Earnings sharing - electric, gas and steam | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 19 | 28 |
| CECONY | Settlement of gas proceedings | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 27 | 27 |
| CECONY | Base rate change deferrals | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 21 | 40 |
| CECONY | Net utility plant reconciliations | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 8 | 15 |
| CECONY | Other | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities – noncurrent | 137 | 145 |
| CECONY | Refundable energy costs | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities—current | 16 | 5 |
| CECONY | Deferred derivative gains | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities—current | 28 | 24 |
| CECONY | Revenue decoupling mechanism | ||
| Regulatory Liabilities [Line Items] | ||
| Regulatory liabilities—current | $ 21 | $ 61 |
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Capitalization - Additional Information (Details) |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2017
USD ($)
shares
|
Dec. 31, 2016
USD ($)
|
|
| Schedule of Capitalization [Line Items] | ||
| Percentage limitation for income available for dividends (not more than) | 100.00% | |
| Rolling average calculation of income available for dividends (years) | 2 years | |
| Long-term debt | $ 16,029,000,000 | $ 14,774,000,000 |
| Non-recourse debt | $ 915,000,000 | 845,000,000 |
| Ratio of consolidated debt to consolidated total capital | 0.51 | |
| Maximum | ||
| Schedule of Capitalization [Line Items] | ||
| Ratio of consolidated debt to consolidated total capital | 0.65 | |
| Transition Bonds, Issued in 2004 | ||
| Schedule of Capitalization [Line Items] | ||
| Long-term debt | $ 7,000,000 | 11,000,000 |
| Level 2 | ||
| Schedule of Capitalization [Line Items] | ||
| Long-term debt, fair value | 17,511,000,000 | |
| Level 3 | ||
| Schedule of Capitalization [Line Items] | ||
| Long-term debt, fair value | 636,000,000 | |
| Notes | ||
| Schedule of Capitalization [Line Items] | ||
| Covenant principal balance amount limit | $ 100,000,000 | |
| Notes | Maximum | ||
| Schedule of Capitalization [Line Items] | ||
| Ratio of consolidated debt to consolidated total capital | 0.675 | |
| CECONY | ||
| Schedule of Capitalization [Line Items] | ||
| Common stock shares, outstanding | shares | 21,976,200 | |
| Long-term debt | $ 13,265,000,000 | 12,073,000,000 |
| Ratio of consolidated debt to consolidated total capital | 0.52 | |
| CECONY | Maximum | ||
| Schedule of Capitalization [Line Items] | ||
| Ratio of consolidated debt to consolidated total capital | 0.65 | |
| Covenant principal balance amount limit | $ 100,000,000 | |
| CECONY | Minimum | ||
| Schedule of Capitalization [Line Items] | ||
| Covenant principal balance amount limit | 150,000,000 | |
| CECONY | Level 2 | ||
| Schedule of Capitalization [Line Items] | ||
| Long-term debt, fair value | 14,527,000,000 | |
| CECONY | Level 3 | ||
| Schedule of Capitalization [Line Items] | ||
| Long-term debt, fair value | 636,000,000 | |
| CECONY | Tax-Exempt Debt | ||
| Schedule of Capitalization [Line Items] | ||
| Tax-exempt debt issued, value | 450,000,000 | |
| Long-term debt | 1,086,000,000 | $ 1,086,000,000 |
| CECONY | Tax-Exempt Debt | Level 3 | ||
| Schedule of Capitalization [Line Items] | ||
| Long-term debt | $ 636,000,000 |
| X | ||||||||||
- Definition Covenant principal balance amount limit No definition available.
|
| X | ||||||||||
- Definition Percentage limitation for income available for dividends No definition available.
|
| X | ||||||||||
- Definition Rolling average calculation of income available for dividends No definition available.
|
| X | ||||||||||
- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Face (par) amount of debt instrument at time of issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. No definition available.
|
| X | ||||||||||
- Definition Amount of debt for which creditor does not have general recourse to the debtor but rather has recourse only to the property used for collateral in the transaction or other specific property. No definition available.
|
| X | ||||||||||
- Definition Indebtedness divided by net capital. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Capitalization - Schedule of Long-Term Debt Maturities (Details) $ in Millions |
Dec. 31, 2017
USD ($)
|
|---|---|
| Debt Instrument [Line Items] | |
| 2018 | $ 1,298 |
| 2019 | 578 |
| 2020 | 791 |
| 2021 | 544 |
| 2022 | 335 |
| CECONY | |
| Debt Instrument [Line Items] | |
| 2018 | 1,200 |
| 2019 | 475 |
| 2020 | 350 |
| 2021 | 0 |
| 2022 | $ 0 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
Capitalization - Carrying Amounts and Fair Values of Long-Term Debt (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Debt Instrument [Line Items] | ||
| Unamortized debt expense | $ 142 | $ 134 |
| Carrying Amount | ||
| Debt Instrument [Line Items] | ||
| Long-Term Debt (including current portion) | 16,029 | 14,774 |
| Fair Value | ||
| Debt Instrument [Line Items] | ||
| Long-Term Debt (including current portion) | 18,147 | 16,093 |
| CECONY | ||
| Debt Instrument [Line Items] | ||
| Unamortized debt discount | 121 | 113 |
| CECONY | Carrying Amount | ||
| Debt Instrument [Line Items] | ||
| Long-Term Debt (including current portion) | 13,265 | 12,073 |
| CECONY | Fair Value | ||
| Debt Instrument [Line Items] | ||
| Long-Term Debt (including current portion) | $ 15,163 | $ 13,268 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of unamortized debt discount (premium) and debt issuance costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. No definition available.
|
| X | ||||||||||
- Definition The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
Short-Term Borrowing (Details) - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Short-term Debt [Line Items] | ||
| Commercial paper, outstanding | $ 577,000,000 | $ 1,054,000,000 |
| Weighted average interest rate | 1.80% | 1.00% |
| Loans outstanding under credit agreement | $ 0 | $ 0 |
| Letters of credit outstanding under the Credit Agreement | $ 0 | 2,000,000 |
| Ratio of consolidated debt to consolidated total capital | 0.51 | |
| Minimum percentage of liens on assets | 5.00% | |
| Maximum | ||
| Short-term Debt [Line Items] | ||
| Ratio of consolidated debt to consolidated total capital | 0.65 | |
| Revolving Credit | ||
| Short-term Debt [Line Items] | ||
| Maximum borrowing capacity | $ 1,500,000,000 | |
| Current amount available | 1,000,000,000 | |
| Letters of Credit | ||
| Short-term Debt [Line Items] | ||
| Maximum borrowing capacity | 1,200,000,000 | |
| CECONY | ||
| Short-term Debt [Line Items] | ||
| Commercial paper, outstanding | $ 150,000,000 | $ 600,000,000 |
| Weighted average interest rate | 1.80% | 1.00% |
| Letters of credit outstanding under the Credit Agreement | $ 2,000,000 | |
| Ratio of consolidated debt to consolidated total capital | 0.52 | |
| CECONY | Maximum | ||
| Short-term Debt [Line Items] | ||
| Ratio of consolidated debt to consolidated total capital | 0.65 | |
| CECONY | Revolving Credit | ||
| Short-term Debt [Line Items] | ||
| Maximum borrowing capacity | $ 2,250,000,000 | |
| X | ||||||||||
- Definition Percentage Of Liens Of Companies Consolidated Asset No definition available.
|
| X | ||||||||||
- Definition Weighted Average Interest Rate Of Commercial Paper No definition available.
|
| X | ||||||||||
- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. No definition available.
|
| X | ||||||||||
- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Carrying value as of the balance sheet date of portion of long-term loans payable due within one year or the operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Indebtedness divided by net capital. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost – including administrative expenses | $ 263 | $ 275 | $ 297 |
| Interest cost on projected benefit obligation | 591 | 596 | 575 |
| Expected return on plan assets | (968) | (947) | (886) |
| Recognition of net actuarial loss | 595 | 596 | 775 |
| Recognition of prior service costs | (17) | 4 | 4 |
| NET PERIODIC BENEFIT COST | 464 | 524 | 765 |
| Amortization of regulatory asset | 0 | 0 | 1 |
| TOTAL PERIODIC BENEFIT COST | 464 | 524 | 766 |
| Cost capitalized | (181) | (214) | (301) |
| Reconciliation to rate level | (34) | 54 | (74) |
| Cost charged to operating expenses | 249 | 364 | 391 |
| CECONY | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost – including administrative expenses | 246 | 258 | 279 |
| Interest cost on projected benefit obligation | 554 | 559 | 538 |
| Expected return on plan assets | (917) | (898) | (840) |
| Recognition of net actuarial loss | 563 | 565 | 734 |
| Recognition of prior service costs | (19) | 2 | 2 |
| NET PERIODIC BENEFIT COST | 427 | 486 | 713 |
| Amortization of regulatory asset | 0 | 0 | 1 |
| TOTAL PERIODIC BENEFIT COST | 427 | 486 | 714 |
| Cost capitalized | (169) | (203) | (285) |
| Reconciliation to rate level | (41) | 58 | (74) |
| Cost charged to operating expenses | $ 217 | $ 341 | 355 |
| Increase in CECONY's pension obligation | $ 45 | ||
| X | ||||||||||
- Definition Defined Benefit Plan Cost Capitalized No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan Cost Charged To Operating Expenses No definition available.
|
| X | ||||||||||
- Definition Effect of Reconciliation to Rate Level No definition available.
|
| X | ||||||||||
- Definition Total Periodic Benefit Cost After Amortization of Regulatory Asset No definition available.
|
| X | ||||||||||
- Definition The expense charged against earnings during the period to allocate the capitalized costs of regulatory assets over the periods expected to benefit from such costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in obligation for pension benefits. Includes, but is not limited to, defined benefit or defined contribution plans. Excludes other postretirement benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Schedule of Funded Status (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | $ 273 | ||
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 330 | $ 273 | |
| Pension Benefits | |||
| CHANGE IN PROJECTED BENEFIT OBLIGATION | |||
| Projected benefit obligation at beginning of year | 14,095 | 14,377 | $ 15,081 |
| Service cost – excluding administrative expenses | 259 | 271 | 293 |
| Interest cost on projected benefit obligation | 591 | 596 | 575 |
| Net actuarial loss/(gain) | 1,231 | (302) | (996) |
| Plan amendments | 6 | (256) | 0 |
| Benefits paid | (646) | (591) | (576) |
| PROJECTED BENEFIT OBLIGATION AT END OF YEAR | 15,536 | 14,095 | 14,377 |
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | 12,472 | 11,759 | 11,495 |
| Actual return on plan assets | 2,041 | 829 | 126 |
| Employer contributions | 450 | 508 | 750 |
| Benefits paid | (646) | (591) | (576) |
| Administrative expenses | (43) | (33) | (36) |
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 14,274 | 12,472 | 11,759 |
| FUNDED STATUS | (1,262) | (1,623) | (2,618) |
| Unrecognized net loss | 2,760 | 3,157 | 3,909 |
| Unrecognized prior service costs | (223) | (244) | 16 |
| Accumulated benefit obligation | 13,897 | 12,655 | 12,909 |
| CECONY | |||
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | 246 | ||
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 301 | 246 | |
| CECONY | Pension Benefits | |||
| CHANGE IN PROJECTED BENEFIT OBLIGATION | |||
| Projected benefit obligation at beginning of year | 13,203 | 13,482 | 14,137 |
| Service cost – excluding administrative expenses | 241 | 254 | 274 |
| Interest cost on projected benefit obligation | 554 | 559 | 538 |
| Net actuarial loss/(gain) | 1,171 | (282) | (931) |
| Plan amendments | 0 | (259) | 0 |
| Benefits paid | (602) | (551) | (536) |
| PROJECTED BENEFIT OBLIGATION AT END OF YEAR | 14,567 | 13,203 | 13,482 |
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | 11,815 | 11,141 | 10,897 |
| Actual return on plan assets | 1,935 | 787 | 118 |
| Employer contributions | 412 | 469 | 697 |
| Benefits paid | (602) | (551) | (536) |
| Administrative expenses | (41) | (31) | (35) |
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 13,519 | 11,815 | 11,141 |
| FUNDED STATUS | (1,048) | (1,388) | (2,341) |
| Unrecognized net loss | 2,624 | 2,995 | 3,704 |
| Unrecognized prior service costs | (242) | (258) | 3 |
| Accumulated benefit obligation | $ 12,972 | $ 11,806 | $ 12,055 |
| X | ||||||||||
- Definition Defined Benefit Plan, Administrative expenses No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan Service Cost Excluding Administrative Expenses No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Unrecognized net loss No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Unrecognized prior service costs No definition available.
|
| X | ||||||||||
- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Amount of contribution received by defined benefit plan from employer which increases plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Additional Information (Details) - USD ($) |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Pension liability | $ 361,000,000 | |||
| Investments value | 330,000,000 | $ 273,000,000 | ||
| CECONY | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Pension liability | 340,000,000 | |||
| Investments value | 301,000,000 | 246,000,000 | ||
| Pension Benefits | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Regulatory assets and liabilities for future income taxes, net | 368,000,000 | |||
| Charge to OCI | 4,000,000 | |||
| Net loss estimated to be amortized | 689,000,000 | |||
| Prior service cost estimated to be amortized | (17,000,000) | |||
| Investments value | 14,274,000,000 | 12,472,000,000 | $ 11,759,000,000 | $ 11,495,000,000 |
| Accumulated benefit obligation | 13,897,000,000 | 12,655,000,000 | 12,909,000,000 | |
| Defined benefit plan, bond amount (excess of) | 50,000,000 | |||
| Estimated future employer contributions | 473,000,000 | |||
| Pension Benefits | CECONY | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Regulatory assets and liabilities for future income taxes, net | 353,000,000 | |||
| Charge to OCI | 1,000,000 | |||
| Net loss estimated to be amortized | 654,000,000 | |||
| Prior service cost estimated to be amortized | (19,000,000) | |||
| Investments value | 13,519,000,000 | 11,815,000,000 | 11,141,000,000 | $ 10,897,000,000 |
| Accumulated benefit obligation | 12,972,000,000 | 11,806,000,000 | $ 12,055,000,000 | |
| Estimated future employer contributions | 435,000,000 | |||
| Other Nonqualified Supplemental Defined Benefit Pension | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Accumulated benefit obligation | 331,000,000 | 303,000,000 | ||
| Other Nonqualified Supplemental Defined Benefit Pension | CECONY | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Accumulated benefit obligation | $ 297,000,000 | $ 268,000,000 |
| X | ||||||||||
- Definition Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Bond Amount No definition available.
|
| X | ||||||||||
- Definition Amount of liability, recognized in statement of financial position, for defined benefit pension plan. Excludes other postretirement benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount included in accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan expected to be recognized in net periodic benefit (cost) credit for fiscal year following most recent annual statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount included in accumulated other comprehensive (income) loss for prior service cost (credit) expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the value of assets that are created when regulatory agencies permits public utilities to defer costs (revenues) to the balance sheet. This element is a the increase (decrease) of regulatory assets and liabilities combined. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after tax, of cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Schedule of Assumptions (Details) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| CECONY | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Rate of compensation increase | 4.25% | 4.25% | 4.25% |
| Rate of compensation increase | 4.25% | 4.25% | 4.25% |
| O&R | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Rate of compensation increase | 4.00% | 4.00% | 4.00% |
| Rate of compensation increase | 4.00% | 4.00% | 4.00% |
| Pension Benefits | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount rate, benefit obligations | 3.70% | 4.25% | 4.25% |
| Discount rate, net periodic benefit cost | 4.25% | 4.25% | 3.90% |
| Expected return on plan assets | 7.50% | 7.80% | 7.80% |
| X | ||||||||||
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Schedule of Expected Benefit Payments (Details) - Pension Benefits $ in Millions |
Dec. 31, 2017
USD ($)
|
|---|---|
| Defined Benefit Plan Disclosure [Line Items] | |
| 2018 | $ 728 |
| 2019 | 738 |
| 2020 | 753 |
| 2021 | 765 |
| 2022 | 778 |
| 2023-2027 | 4,083 |
| CECONY | |
| Defined Benefit Plan Disclosure [Line Items] | |
| 2018 | 677 |
| 2019 | 686 |
| 2020 | 700 |
| 2021 | 712 |
| 2022 | 724 |
| 2023-2027 | $ 3,804 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Schedule of Plan Assets Allocations (Details) - Pension Benefits |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|---|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 100.00% | ||
| Plan Assets Percentage | 100.00% | 100.00% | 100.00% |
| Equity Securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Plan Assets Percentage | 58.00% | 58.00% | 57.00% |
| Equity Securities | Minimum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 53.00% | ||
| Equity Securities | Maximum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 63.00% | ||
| Debt Securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Plan Assets Percentage | 33.00% | 33.00% | 33.00% |
| Debt Securities | Minimum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 0.28% | ||
| Debt Securities | Maximum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 0.38% | ||
| Real Estate | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Plan Assets Percentage | 9.00% | 9.00% | 10.00% |
| Real Estate | Minimum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 7.00% | ||
| Real Estate | Maximum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 11.00% |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Schedule of Fair Value of Plan Assets (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|---|
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | $ 330 | $ 273 | ||
| Private Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 247 | |||
| Real Estate | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 1,139 | |||
| Pension Benefits | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Funds for retiree health benefits | (262) | (270) | ||
| Funds for retiree health benefits measured at NAV per share (l)(n) | (36) | (37) | ||
| Total funds for retiree health benefits | (298) | 307 | ||
| Investments (excluding funds for retiree health benefits) | 14,683 | 12,910 | ||
| Pending activities | (409) | (438) | ||
| Total fair value of plan net assets | 14,274 | 12,472 | $ 11,759 | $ 11,495 |
| Pension Benefits | U.S. Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 3,900 | 3,466 | ||
| Pension Benefits | International Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 4,132 | 3,558 | ||
| Pension Benefits | U.S. Government Issued Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 1,786 | 1,337 | ||
| Pension Benefits | Corporate Bonds Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 2,450 | 2,140 | ||
| Pension Benefits | Structured Assets Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 3 | 1 | ||
| Pension Benefits | Other Fixed Income Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 125 | 200 | ||
| Pension Benefits | Cash and Cash Equivalents | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 476 | 536 | ||
| Pension Benefits | Futures | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 308 | 364 | ||
| Pension Benefits | Total investments | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 13,180 | 11,602 | ||
| Pension Benefits | Private Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 336 | |||
| Pension Benefits | Real Estate | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 1,214 | |||
| Pension Benefits | Hedge Funds | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 251 | 229 | ||
| Pension Benefits | Investments Valued Using NAV Per Share | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 1,801 | 1,615 | ||
| Pension Benefits | Level 1 | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Funds for retiree health benefits | (168) | (165) | ||
| Investments (excluding funds for retiree health benefits) | 8,268 | 6,931 | ||
| Pension Benefits | Level 1 | U.S. Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 3,872 | 3,466 | ||
| Pension Benefits | Level 1 | International Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 4,132 | 3,187 | ||
| Pension Benefits | Level 1 | U.S. Government Issued Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Pension Benefits | Level 1 | Corporate Bonds Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Pension Benefits | Level 1 | Structured Assets Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Pension Benefits | Level 1 | Other Fixed Income Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Pension Benefits | Level 1 | Cash and Cash Equivalents | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 124 | 147 | ||
| Pension Benefits | Level 1 | Futures | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 308 | 296 | ||
| Pension Benefits | Level 1 | Total investments | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 8,436 | 7,096 | ||
| Pension Benefits | Level 2 | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Funds for retiree health benefits | (94) | (105) | ||
| Investments (excluding funds for retiree health benefits) | 4,650 | 4,401 | ||
| Pension Benefits | Level 2 | U.S. Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 28 | |||
| Pension Benefits | Level 2 | International Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 371 | |||
| Pension Benefits | Level 2 | U.S. Government Issued Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 1,786 | 1,337 | ||
| Pension Benefits | Level 2 | Corporate Bonds Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 2,450 | 2,140 | ||
| Pension Benefits | Level 2 | Structured Assets Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 3 | 1 | ||
| Pension Benefits | Level 2 | Other Fixed Income Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 125 | 200 | ||
| Pension Benefits | Level 2 | Cash and Cash Equivalents | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 352 | 389 | ||
| Pension Benefits | Level 2 | Futures | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 68 | |||
| Pension Benefits | Level 2 | Total investments | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | $ 4,744 | $ 4,506 |
| X | ||||||||||
- Definition Defined Benefit Plan, Pending activities No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Retiree Health Benefit Fund No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Retiree Health Benefit, Fund Measured at Net Asset Value Per Share No definition available.
|
| X | ||||||||||
- Definition Investments, excluding funds for retiree health benefits, total No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Liability for extension of health coverage in instances where coverage under the plan would otherwise end. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Pension Benefits - Schedule of Employer Contribution to Defined Savings Plan (Details) - Defined Contribution Savings Plan - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Employer contribution to the defined savings plan | $ 40 | $ 36 | $ 34 |
| CECONY | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Employer contribution to the defined savings plan | $ 35 | $ 32 | $ 29 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Net Periodic Postretirement Benefit Costs (Details) - Other Postretirement Benefits - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | $ 20 | $ 18 | $ 20 |
| Interest cost on accumulated other postretirement benefit obligation | 46 | 48 | 51 |
| Expected return on plan assets | (69) | (77) | (78) |
| Recognition of net actuarial loss | 2 | 5 | 31 |
| Recognition of prior service cost | (17) | (20) | (20) |
| NET PERIODIC BENEFIT COST | (18) | (26) | 4 |
| Cost capitalized | 8 | 11 | (2) |
| Reconciliation to rate level | (4) | 22 | 14 |
| Cost charged to operating expenses | (14) | 7 | 16 |
| CECONY | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | 13 | 13 | 15 |
| Interest cost on accumulated other postretirement benefit obligation | 38 | 40 | 43 |
| Expected return on plan assets | (61) | (67) | (68) |
| Recognition of net actuarial loss | (3) | 3 | 28 |
| Recognition of prior service cost | (11) | (14) | (14) |
| NET PERIODIC BENEFIT COST | (24) | (25) | 4 |
| Cost capitalized | 10 | 10 | (2) |
| Reconciliation to rate level | (2) | 22 | 6 |
| Cost charged to operating expenses | $ (16) | $ 7 | $ 8 |
| X | ||||||||||
- Definition Defined Benefit Plan Cost Capitalized No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan Cost Charged To Operating Expenses No definition available.
|
| X | ||||||||||
- Definition Effect of Reconciliation to Rate Level No definition available.
|
| X | ||||||||||
- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Schedule of Funded Status (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | $ 273 | ||
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 330 | $ 273 | |
| CECONY | |||
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | 246 | ||
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 301 | 246 | |
| Other Postretirement Benefits | |||
| CHANGE IN BENEFIT OBLIGATION | |||
| Projected benefit obligation at beginning of year | 1,198 | 1,287 | $ 1,411 |
| Service cost | 20 | 18 | 20 |
| Interest cost on accumulated other postretirement benefit obligation | 46 | 48 | 51 |
| Amendments | 0 | 0 | 0 |
| Net actuarial loss/(gain) | 53 | (57) | (103) |
| Benefits paid and administrative expenses | (134) | (134) | (127) |
| Participant contributions | 36 | 36 | 35 |
| PROJECTED BENEFIT OBLIGATION AT END OF YEAR | 1,219 | 1,198 | 1,287 |
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | 975 | 994 | 1,084 |
| Actual return on plan assets | 150 | 60 | (6) |
| Employer contributions | 17 | 7 | 6 |
| EGWP payments | 34 | 35 | 28 |
| Participant contributions | 35 | 36 | 35 |
| Benefits paid | (172) | (157) | (153) |
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 1,039 | 975 | 994 |
| FUNDED STATUS | (180) | (223) | (293) |
| Unrecognized net loss/(gain) | (47) | (24) | 28 |
| Unrecognized prior service costs | (14) | (31) | (51) |
| Other Postretirement Benefits | CECONY | |||
| CHANGE IN BENEFIT OBLIGATION | |||
| Projected benefit obligation at beginning of year | 1,007 | 1,093 | 1,203 |
| Service cost | 13 | 13 | 15 |
| Interest cost on accumulated other postretirement benefit obligation | 38 | 40 | 43 |
| Amendments | 0 | 0 | 0 |
| Net actuarial loss/(gain) | 16 | (52) | (85) |
| Benefits paid and administrative expenses | (124) | (122) | (117) |
| Participant contributions | 35 | 35 | 34 |
| PROJECTED BENEFIT OBLIGATION AT END OF YEAR | 985 | 1,007 | 1,093 |
| CHANGE IN PLAN ASSETS | |||
| Fair value of plan assets at beginning of year | 851 | 870 | 950 |
| Actual return on plan assets | 130 | 52 | (4) |
| Employer contributions | 8 | 7 | 6 |
| EGWP payments | 30 | 33 | 26 |
| Participant contributions | 35 | 35 | 34 |
| Benefits paid | (161) | (146) | (142) |
| FAIR VALUE OF PLAN ASSETS AT END OF YEAR | 893 | 851 | 870 |
| FUNDED STATUS | (92) | (156) | (223) |
| Unrecognized net loss/(gain) | (85) | (42) | 4 |
| Unrecognized prior service costs | $ (7) | $ (18) | $ (32) |
| X | ||||||||||
- Definition Defined Benefit Plan, benefits paid and administrative expenses No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan Employer Group Waiver Plan Payments No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Unrecognized net loss No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Unrecognized prior service costs No definition available.
|
| X | ||||||||||
- Definition Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of contributions received by defined benefit plan from participant which increase benefit obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Amount of contribution received by defined benefit plan from employer which increases plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of contributions received by defined benefit plan from participant which increases plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Additional Information (Details) - Other Postretirement Benefits $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
USD ($)
| |
| Defined Benefit Plan Disclosure [Line Items] | |
| Decrease in liability for other postretirement benefits | $ 43 |
| Increase in regulatory liabilities | 11 |
| Net losses unrecognized to be amortized | 8 |
| Prior service cost estimated to be amortized | $ (6) |
| Health care cost trend rate for net periodic benefit cost, current | 5.80% |
| Health care cost trend rate for net periodic benefit cost | 4.50% |
| Health care cost trend rate for benefit obligations, current | 5.60% |
| Health care cost trend rate for benefit obligations | 4.50% |
| Expected contributions | $ 7 |
| Clean Energy Businesses, Con Edison Transmission and RECO | |
| Defined Benefit Plan Disclosure [Line Items] | |
| Debit to OCI (net of taxes) for unrecognized net losses | 3 |
| Change to OCI (net of taxes) for unrecognized prior service costs | 0 |
| CECONY | |
| Defined Benefit Plan Disclosure [Line Items] | |
| Decrease in liability for other postretirement benefits | 64 |
| Increase in regulatory liabilities | 32 |
| Net losses unrecognized to be amortized | 1 |
| Prior service cost estimated to be amortized | $ (2) |
| X | ||||||||||
- Definition Defined Benefit Plan, Health Care Cost Trend Rate, current No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Health Care Cost Trend Rate, current, benefit obligations No definition available.
|
| X | ||||||||||
- Definition Defined benefit plan, ultimate health care cost trend rate benefit obligations. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount included in accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan expected to be recognized in net periodic benefit (cost) credit for fiscal year following most recent annual statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount included in accumulated other comprehensive (income) loss for prior service cost (credit) expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Ultimate trend rate for health care cost for defined benefit postretirement plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in obligation for other postretirement benefits. Includes, but is not limited to, defined benefit and defined contribution plans. Excludes pension benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The increase (decrease) during the reporting period in the value of assets that are created when regulatory agencies permits public utilities to defer costs (revenues) to the balance sheet. This element is a the increase (decrease) of regulatory assets and liabilities combined. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, after tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Schedule of Actuarial Assumptions (Details) - Other Postretirement Benefits |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Expected Return on Plan Assets | 7.50% | 7.00% | 7.75% |
| CECONY | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount Rate, Benefit Obligations | 3.55% | 4.00% | 4.05% |
| Discount rate, net periodic benefit cost | 4.00% | 4.05% | 3.75% |
| O&R | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Discount Rate, Benefit Obligations | 3.70% | 4.20% | 4.20% |
| Discount rate, net periodic benefit cost | 4.20% | 4.20% | 3.85% |
| X | ||||||||||
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Schedule of Change of Assumed Health Care Cost Trend Rate (Details) - Other Postretirement Benefits $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
USD ($)
| |
| Increase | |
| Effect on accumulated other postretirement benefit obligation | $ 13 |
| Effect on service cost and interest cost components for 2017 | 2 |
| Decrease | |
| Effect on accumulated other postretirement benefit obligation | 11 |
| Effect on service cost and interest cost components for 2017 | 0 |
| CECONY | |
| Increase | |
| Effect on accumulated other postretirement benefit obligation | (20) |
| Effect on service cost and interest cost components for 2017 | (1) |
| Decrease | |
| Effect on accumulated other postretirement benefit obligation | 35 |
| Effect on service cost and interest cost components for 2017 | $ 1 |
| X | ||||||||||
- Definition Defined Benefit Plan, Effect of One Percentage Point Decrease [Abstract] No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Effect of One Percentage Point Increase [Abstract] No definition available.
|
| X | ||||||||||
- Definition Amount of decrease in accumulated postretirement benefit obligation from one-percentage-point decrease in assumed health care cost trend rate. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in service and interest cost components of net periodic postretirement benefit cost from one-percentage-point decrease in assumed health care cost trend rate. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase in accumulated postretirement benefit obligation from one-percentage-point increase in assumed health care cost trend rate. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase in service and interest cost components of net periodic postretirement benefit cost from one-percentage-point increase in assumed health care cost trend rate. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Schedule of Expected Benefit Payments (Details) - Other Postretirement Benefits $ in Millions |
Dec. 31, 2017
USD ($)
|
|---|---|
| Defined Benefit Plan Disclosure [Line Items] | |
| 2018 | $ 83 |
| 2019 | 81 |
| 2020 | 78 |
| 2021 | 76 |
| 2022 | 75 |
| 2023-2027 | 363 |
| CECONY | |
| Defined Benefit Plan Disclosure [Line Items] | |
| 2018 | 73 |
| 2019 | 70 |
| 2020 | 67 |
| 2021 | 65 |
| 2022 | 64 |
| 2023-2027 | $ 303 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Schedule of Plan Assets Allocations (Details) - Other Postretirement Benefits - CECONY |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|---|
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 100.00% | ||
| Plan Assets Percentage | 100.00% | 100.00% | 100.00% |
| Equity Securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Plan Assets Percentage | 60.00% | 60.00% | 59.00% |
| Equity Securities | Minimum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 50.00% | ||
| Equity Securities | Maximum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 80.00% | ||
| Debt Securities | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Plan Assets Percentage | 40.00% | 40.00% | 41.00% |
| Debt Securities | Minimum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 20.00% | ||
| Debt Securities | Maximum | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Target Allocation Range | 50.00% |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Postretirement Benefits - Schedule of Fair Values of Plan Assets (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|---|
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | $ 330 | $ 273 | ||
| Other Postretirement Benefits | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Funds for retiree health benefits | 262 | 270 | ||
| Investments (including funds for retiree health benefits) | 984 | 924 | ||
| Funds for retiree health benefits measured at NAV per share (l)(n) | 36 | 37 | ||
| Pending activities | 19 | 14 | ||
| Total fair value of plan net assets | 1,039 | 975 | $ 994 | $ 1,084 |
| Other Postretirement Benefits | Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 420 | 391 | ||
| Other Postretirement Benefits | Other Fixed Income Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 286 | 250 | ||
| Other Postretirement Benefits | Cash and Cash Equivalents | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 16 | 13 | ||
| Other Postretirement Benefits | Total investments | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 722 | 654 | ||
| Other Postretirement Benefits | Level 1 | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Funds for retiree health benefits | 168 | 165 | ||
| Investments (including funds for retiree health benefits) | 168 | 165 | ||
| Other Postretirement Benefits | Level 1 | Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Other Postretirement Benefits | Level 1 | Other Fixed Income Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Other Postretirement Benefits | Level 1 | Cash and Cash Equivalents | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Other Postretirement Benefits | Level 1 | Total investments | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 0 | 0 | ||
| Other Postretirement Benefits | Level 2 | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Funds for retiree health benefits | 94 | 105 | ||
| Investments (including funds for retiree health benefits) | 816 | 759 | ||
| Other Postretirement Benefits | Level 2 | Equity | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 420 | 391 | ||
| Other Postretirement Benefits | Level 2 | Other Fixed Income Debt | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 286 | 250 | ||
| Other Postretirement Benefits | Level 2 | Cash and Cash Equivalents | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | 16 | 13 | ||
| Other Postretirement Benefits | Level 2 | Total investments | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Total fair value of plan net assets | $ 722 | $ 654 |
| X | ||||||||||
- Definition Defined Benefit Plan, Pending activities No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Retiree Health Benefit Fund No definition available.
|
| X | ||||||||||
- Definition Defined Benefit Plan, Retiree Health Benefit, Fund Measured at Net Asset Value Per Share No definition available.
|
| X | ||||||||||
- Definition Investments including funds for retiree health benefits total. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Site Contingency [Line Items] | ||
| Accrued Liabilities | $ 737 | $ 753 |
| Regulatory assets | 4,333 | 7,124 |
| Manufactured gas plant sites | ||
| Site Contingency [Line Items] | ||
| Accrued Liabilities | 651 | 664 |
| Other Superfund Sites | ||
| Site Contingency [Line Items] | ||
| Accrued Liabilities | 86 | 89 |
| Superfund Sites | ||
| Site Contingency [Line Items] | ||
| Accrued Liabilities | 737 | 753 |
| Regulatory assets | 793 | 823 |
| CECONY | ||
| Site Contingency [Line Items] | ||
| Accrued Liabilities | 637 | 655 |
| Regulatory assets | 3,925 | 6,563 |
| CECONY | Manufactured gas plant sites | ||
| Site Contingency [Line Items] | ||
| Accrued Liabilities | 551 | 567 |
| CECONY | Other Superfund Sites | ||
| Site Contingency [Line Items] | ||
| Accrued Liabilities | 86 | 88 |
| CECONY | Superfund Sites | ||
| Site Contingency [Line Items] | ||
| Accrued Liabilities | 637 | 655 |
| Regulatory assets | $ 677 | $ 711 |
| X | ||||||||||
- Definition Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable after twelve months or beyond the next operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Environmental Matters - Environmental Remediation Costs (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Environmental Exit Cost [Line Items] | ||
| Remediation costs incurred | $ 24 | $ 34 |
| CECONY | ||
| Environmental Exit Cost [Line Items] | ||
| Remediation costs incurred | $ 19 | $ 21 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
Environmental Matters - Additional Information (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Site Contingency [Line Items] | ||
| Insurance recoveries received | $ 0 | $ 1 |
| Asbestos Proceedings | ||
| Site Contingency [Line Items] | ||
| Estimated undiscounted asbestos liability (years) | 15 years | |
| Superfund Sites | ||
| Site Contingency [Line Items] | ||
| Remediation cost estimate | $ 47 | |
| Superfund Sites | Manufactured Gas Plant Sites | Maximum | ||
| Site Contingency [Line Items] | ||
| Estimated aggregate undiscounted potential liability related environmental contaminants (up to) | 2,700 | |
| CECONY | ||
| Site Contingency [Line Items] | ||
| Insurance recoveries received | $ 0 | $ 1 |
| CECONY | Asbestos Proceedings | ||
| Site Contingency [Line Items] | ||
| Estimated undiscounted asbestos liability (years) | 15 years | |
| CECONY | Superfund Sites | ||
| Site Contingency [Line Items] | ||
| Remediation cost estimate | $ 34 | |
| CECONY | Superfund Sites | Manufactured Gas Plant Sites | Maximum | ||
| Site Contingency [Line Items] | ||
| Estimated aggregate undiscounted potential liability related environmental contaminants (up to) | $ 2,500 | |
| X | ||||||||||
- Definition Estimated Undiscounted Asbestos Liability, Period No definition available.
|
| X | ||||||||||
- Definition Potential undiscounted liability for environmental loss contingencies gross. No definition available.
|
| X | ||||||||||
- Definition The amount recovered from insurance. These recoveries reduce costs and losses that are reported as a separate line item under operating expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Best estimate of the loss exposure for reasonably possible environmental contingencies at an individual site for which no accrual has been recorded. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Environmental Matters - Accrued Liability for Asbestos Suits and Workers' Compensation Proceedings (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Site Contingency [Line Items] | ||
| Regulatory assets | $ 4,333 | $ 7,124 |
| Asbestos Suits | ||
| Site Contingency [Line Items] | ||
| Accrued liability | 8 | 8 |
| Regulatory assets | 8 | 8 |
| Workers' Compensation | ||
| Site Contingency [Line Items] | ||
| Accrued liability | 84 | 88 |
| Regulatory assets | 10 | 13 |
| CECONY | ||
| Site Contingency [Line Items] | ||
| Regulatory assets | 3,925 | 6,563 |
| CECONY | Asbestos Suits | ||
| Site Contingency [Line Items] | ||
| Accrued liability | 7 | 7 |
| Regulatory assets | 7 | 7 |
| CECONY | Workers' Compensation | ||
| Site Contingency [Line Items] | ||
| Accrued liability | 80 | 83 |
| Regulatory assets | $ 10 | $ 13 |
| X | ||||||||||
- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Material Contingencies - Manhattan Explosion and Fire (Details) $ in Millions |
1 Months Ended | |||
|---|---|---|---|---|
|
Mar. 12, 2014
building
people
|
Feb. 28, 2017
USD ($)
|
Dec. 31, 2017
USD ($)
lawsuit
|
Dec. 31, 2016
USD ($)
|
|
| Loss Contingencies [Line Items] | ||||
| Accrued regulatory liability | $ 4,577 | $ 1,905 | ||
| Settlement of gas proceedings | ||||
| Loss Contingencies [Line Items] | ||||
| Accrued regulatory liability | $ 27 | $ 27 | ||
| Manhattan Explosion and Fire | ||||
| Loss Contingencies [Line Items] | ||||
| Number of buildings destroyed by fire | building | 2 | |||
| Number of people died in explosion and fire incident | people | 8 | |||
| Number of people injured in explosion and fire incident (more than) | people | 50 | |||
| Amount of costs that will not recover from customers | $ 126 | |||
| Number of pending lawsuits | lawsuit | 80 | |||
| Manhattan Explosion and Fire | Settlement of gas proceedings | ||||
| Loss Contingencies [Line Items] | ||||
| Accrued regulatory liability | $ 27 |
| X | ||||||||||
- Definition Number of people died in explosion and fire incident. No definition available.
|
| X | ||||||||||
- Definition Number of people injured in explosion and fire incident. No definition available.
|
| X | ||||||||||
- Definition Number of Buildings Destroyed by Fire No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The amount of loss pertaining to the specified contingency that was charged against earnings in the period, including the effects of revisions in previously reported estimates. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Number of pending claims pertaining to a loss contingency. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Other Material Contingencies - Guarantees (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Commitments and Contingencies Disclosure [Abstract] | ||
| Guarantee obligations maximum exposure | $ 2,073 | $ 2,370 |
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
Other Material Contingencies - Total Guarantees (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | $ 2,073 | $ 2,370 |
| Con Edison Transmission | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 1,047 | |
| Energy transactions | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 669 | |
| Renewable electric production projects | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 234 | |
| Other | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 123 | |
| 0 – 3 years | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 1,407 | |
| 0 – 3 years | Con Edison Transmission | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 643 | |
| 0 – 3 years | Energy transactions | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 431 | |
| 0 – 3 years | Renewable electric production projects | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 210 | |
| 0 – 3 years | Other | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 123 | |
| 4 – 10 years | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 431 | |
| 4 – 10 years | Con Edison Transmission | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 404 | |
| 4 – 10 years | Energy transactions | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 27 | |
| 4 – 10 years | Renewable electric production projects | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 0 | |
| 4 – 10 years | Other | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 0 | |
| Greater than 10 years | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 235 | |
| Greater than 10 years | Con Edison Transmission | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 0 | |
| Greater than 10 years | Energy transactions | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 211 | |
| Greater than 10 years | Renewable electric production projects | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | 24 | |
| Greater than 10 years | Other | ||
| Guarantor Obligations [Line Items] | ||
| Total guarantees, by type and term | $ 0 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Other Material Contingencies - Con Edison Transmission (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2014 |
|
| Guarantor Obligations [Line Items] | |||
| Guarantee obligations maximum exposure | $ 2,073 | $ 2,370 | |
| Payment Guarantee by CET Electric of Contributions to New York Transco LLC | |||
| Guarantor Obligations [Line Items] | |||
| Ownership interest, percentage | 45.70% | ||
| Estimated project cost percentage | 175.00% | ||
| Financial Guarantee in Behalf of CET Gas for Proposed Gas Transmission Project | |||
| Guarantor Obligations [Line Items] | |||
| Guarantee obligations maximum exposure | $ 25 |
| X | ||||||||||
- Definition Percentage of estimated costs on projects. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. No definition available.
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Other Material Contingencies - Other (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Guarantor Obligations [Line Items] | ||
| Guarantee obligations maximum exposure | $ 2,073 | $ 2,370 |
| Financial Guarantee for Indemnity Agreements for Surety Bonds in Connection with Operation of Solar Energy Facilities and Energy Service Projects | ||
| Guarantor Obligations [Line Items] | ||
| Guarantee obligations maximum exposure | 70 | |
| Certain Obligations Under Agreement to Sell the Retail Electric Supply Business | ||
| Guarantor Obligations [Line Items] | ||
| Guarantee obligations maximum exposure | $ 53 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
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Electricity Purchase Agreements - Summary of Significant Terms of Electricity Purchase Agreements (Details) |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
MW
| |
| Brooklyn Navy Yard | |
| Long-term Contract for Purchase of Electric Power [Line Items] | |
| Plant Output (MW) | 322 |
| Contracted Output (MW) | 303 |
| Contract Term (Years) | 40 years |
| Indian Point | |
| Long-term Contract for Purchase of Electric Power [Line Items] | |
| Plant Output (MW) | 2,150 |
| Contracted Output (MW) | 500 |
| Contract Term (Years) | 16 years |
| X | ||||||||||
- Definition Long Term Contract For Purchase Of Electric Power Megawatts No definition available.
|
| X | ||||||||||
- Definition Power Plant Output No definition available.
|
| X | ||||||||||
- Definition Term of power purchase agreement years. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Electricity Purchase Agreements - Summary of Estimated Capacity and Other Fixed Payments (Details) $ in Millions |
Dec. 31, 2017
USD ($)
|
|---|---|
| Long-term Contract for Purchase of Electric Power [Line Items] | |
| 2018 | $ 257 |
| 2019 | 202 |
| 2020 | 114 |
| 2021 | 65 |
| 2022 | 54 |
| All Years Thereafter | 656 |
| CECONY | |
| Long-term Contract for Purchase of Electric Power [Line Items] | |
| 2018 | 255 |
| 2019 | 198 |
| 2020 | 111 |
| 2021 | 64 |
| 2022 | 54 |
| All Years Thereafter | $ 656 |
| X | ||||||||||
- Definition Amount of contractual obligation due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
|
| X | ||||||||||
- Definition Amount of contractual obligation due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
|
| X | ||||||||||
- Definition Amount of contractual obligation due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
|
| X | ||||||||||
- Definition Amount of contractual obligation due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
|
| X | ||||||||||
- Definition Amount of contractual obligation due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
|
| X | ||||||||||
- Definition Amount of contractual obligation due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
|
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Electricity Purchase Agreements - Summary of Capacity, Energy and Other Fixed Payments (Details) - CECONY - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | $ 552 | $ 692 | $ 865 |
| Linden Cogeneration | |||
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | 114 | 304 | 323 |
| Indian Point | |||
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | 211 | 203 | 226 |
| Astoria Energy | |||
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | 0 | 50 | 178 |
| Astoria Generating Company | |||
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | 92 | 16 | 0 |
| Brooklyn Navy Yard | |||
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | 117 | 119 | 113 |
| Indeck Corinth | |||
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | 0 | 0 | 25 |
| Cogen Technologies | |||
| Long-term Contract for Purchase of Electric Power [Line Items] | |||
| Capacity, energy and other fixed payments | $ 18 | $ 0 | $ 0 |
| X | ||||||||||
- Definition Long-term Contract for Purchase of Capacity and Energy, Amount of Fixed Payments No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Leases - Schedule of Capital Leases (Details) - Common - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Property Subject to or Available for Operating Lease [Line Items] | ||
| Utility Plant | $ 2 | $ 3 |
| CECONY | ||
| Property Subject to or Available for Operating Lease [Line Items] | ||
| Utility Plant | $ 1 | $ 2 |
| X | ||||||||||
- Definition Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Leases - Additional Information (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Operating Leased Assets [Line Items] | ||
| Accumulated amortization | $ 3 | $ 3 |
| CECONY | ||
| Operating Leased Assets [Line Items] | ||
| Accumulated amortization | $ 2 | $ 1 |
| Increase in annual payments, percentage | 2.18% | |
| Decrease in transformer installations, percentage | 0.50% |
| X | ||||||||||
- Definition Capital Leases Accumulated Amortization No definition available.
|
| X | ||||||||||
- Definition Operating Leases, Increase in Annual Payments, Percentage No definition available.
|
| X | ||||||||||
- Definition Public Utility, Decrease in Installation Costs, Percentage No definition available.
|
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Leases - Future Minimum Rental Payments for Operating Leases (Details) $ in Millions |
Dec. 31, 2017
USD ($)
|
|---|---|
| Operating Leased Assets [Line Items] | |
| 2018 | $ 63 |
| 2019 | 63 |
| 2020 | 63 |
| 2021 | 62 |
| 2022 | 59 |
| All years thereafter | 746 |
| Total | 1,056 |
| CECONY | |
| Operating Leased Assets [Line Items] | |
| 2018 | 55 |
| 2019 | 56 |
| 2020 | 55 |
| 2021 | 54 |
| 2022 | 53 |
| All years thereafter | 645 |
| Total | $ 918 |
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Future minimum rental payments in aggregate as of the balance sheet date under operating leases. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Future rental payments receivable within one year of the balance sheet date under an operating lease. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Future rental payments receivable within the fifth year from the balance sheet date under an operating lease. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Future rental payments receivable within the fourth year from the balance sheet date under an operating lease. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Future rental payments receivable within the third year from the balance sheet date under an operating lease. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Future rental payments receivable within the second year from the balance sheet date under an operating lease. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Goodwill and Other Intangible Assets (Details) |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
business_acquisition
|
Dec. 31, 2015
USD ($)
|
|
| Goodwill [Line Items] | |||
| Goodwill | $ 428,000,000 | $ 428,000,000 | |
| Impairment charge | 0 | ||
| Finite lived intangible assets, accumulated amortization | 15,000,000 | 6,000,000 | |
| Amortization expense | 9,000,000 | 2,000,000 | $ 0 |
| Intangibles Future Amortization: | |||
| Year 1 | 9,000,000 | ||
| Year 2 | 9,000,000 | ||
| Year 3 | 9,000,000 | ||
| Year 4 | 9,000,000 | ||
| Year 5 | 9,000,000 | ||
| Other Intangible Assets | |||
| Goodwill [Line Items] | |||
| Finite lived intangible assets, net | 0 | 5,000,000 | |
| Finite lived intangible assets, accumulated amortization | 6,000,000 | 5,000,000 | |
| CECONY | |||
| Goodwill [Line Items] | |||
| Goodwill | 245,000,000 | 245,000,000 | |
| CECONY | Other Intangible Assets | |||
| Goodwill [Line Items] | |||
| Finite lived intangible assets, net | 0 | 0 | |
| O&R | |||
| Goodwill [Line Items] | |||
| Goodwill | 161,000,000 | 161,000,000 | |
| O&R Merger | |||
| Goodwill [Line Items] | |||
| Goodwill | 406,000,000 | 406,000,000 | |
| Gas Storage Company | CET Gas | |||
| Goodwill [Line Items] | |||
| Goodwill | 8,000,000 | 8,000,000 | |
| Energy Services Company | Clean Energy Businesses | |||
| Goodwill [Line Items] | |||
| Goodwill | $ 15,000,000 | ||
| Number of businesses acquired included in goodwill impairment test | business_acquisition | 2 | ||
| Impairment charge | $ 15,000,000 | ||
| Impairment charge, net of tax | 12,000,000 | ||
| Residential Solar Company | Clean Energy Businesses | |||
| Goodwill [Line Items] | |||
| Goodwill | 14,000,000 | ||
| Power Purchase | |||
| Goodwill [Line Items] | |||
| Finite lived intangible assets, net | 131,000,000 | 119,000,000 | |
| Finite lived intangible assets, accumulated amortization | $ 9,000,000 | $ 1,000,000 | |
| X | ||||||||||
- Definition Number of Businesses Included in Goodwill Impairment Test No definition available.
|
| X | ||||||||||
- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
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- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
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- Definition Amount after tax of loss recognized that results from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. No definition available.
|
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Income Tax - Schedule of Components of Income Tax (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| State | |||
| Current | $ (2) | $ (42) | $ 38 |
| Deferred | 103 | 188 | 93 |
| Federal | |||
| Current | (11) | (43) | (86) |
| Deferred | 391 | 604 | 569 |
| Amortization of investment tax credits | (9) | (9) | (9) |
| Total income tax expense | 472 | 698 | 605 |
| CECONY | |||
| State | |||
| Current | 37 | (1) | 48 |
| Deferred | 75 | 114 | 82 |
| Federal | |||
| Current | 73 | 59 | 77 |
| Deferred | 504 | 435 | 372 |
| Amortization of investment tax credits | (4) | (4) | (5) |
| Total income tax expense | $ 685 | $ 603 | $ 574 |
| X | ||||||||||
- Definition Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Income Tax - Schedule of Differences on Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Deferred tax liabilities: | ||
| Property basis differences | $ 6,555 | $ 9,446 |
| Regulatory assets: | ||
| Unrecognized pension and other postretirement costs | 697 | 1,162 |
| Future income tax | 0 | 986 |
| Environmental remediation costs | 219 | 333 |
| Deferred storm costs | 11 | 23 |
| Other regulatory assets | 269 | 371 |
| Equity investments | 263 | 363 |
| Total deferred tax liabilities | 8,014 | 12,684 |
| Deferred tax assets: | ||
| Accrued pension and other postretirement costs | 264 | 581 |
| Future income tax | 698 | 0 |
| Other regulatory liabilities | 593 | 822 |
| Superfund and other environmental costs | 203 | 304 |
| Asset retirement obligations | 86 | 99 |
| Loss carryforwards | 95 | 59 |
| Tax credits carryforward | 658 | 498 |
| Valuation allowance | (33) | (16) |
| Other | 112 | 303 |
| Total deferred tax assets | 2,676 | 2,650 |
| Net deferred tax liabilities | 5,338 | 10,034 |
| Unamortized investment tax credits | 157 | 171 |
| Net deferred tax liabilities and unamortized investment tax credits | 5,495 | 10,205 |
| CECONY | ||
| Deferred tax liabilities: | ||
| Property basis differences | 5,968 | 8,620 |
| Regulatory assets: | ||
| Unrecognized pension and other postretirement costs | 656 | 1,104 |
| Future income tax | 0 | 940 |
| Environmental remediation costs | 187 | 287 |
| Deferred storm costs | 0 | 1 |
| Other regulatory assets | 241 | 321 |
| Equity investments | 0 | 0 |
| Total deferred tax liabilities | 7,052 | 11,273 |
| Deferred tax assets: | ||
| Accrued pension and other postretirement costs | 187 | 467 |
| Future income tax | 660 | 0 |
| Other regulatory liabilities | 524 | 728 |
| Superfund and other environmental costs | 176 | 265 |
| Asset retirement obligations | 79 | 92 |
| Loss carryforwards | 0 | 0 |
| Tax credits carryforward | 0 | 0 |
| Valuation allowance | 0 | 0 |
| Other | 148 | 312 |
| Total deferred tax assets | 1,774 | 1,864 |
| Net deferred tax liabilities | 5,278 | 9,409 |
| Unamortized investment tax credits | 28 | 41 |
| Net deferred tax liabilities and unamortized investment tax credits | $ 5,306 | $ 9,450 |
| X | ||||||||||
- Definition Deferred Tax Assets Asset Retirement Obligations No definition available.
|
| X | ||||||||||
- Definition Deferred Tax Assets, Pension and other postretirement costs No definition available.
|
| X | ||||||||||
- Definition Deferred Tax Assets, Regulatory Assets And Liabilities, Future Income Tax No definition available.
|
| X | ||||||||||
- Definition Deferred Tax Assets, Regulatory Assets And Liabilities, Other No definition available.
|
| X | ||||||||||
- Definition Deferred tax assets superfund and environmental costs. No definition available.
|
| X | ||||||||||
- Definition Deferred tax liabilities environmental redemption costs. No definition available.
|
| X | ||||||||||
- Definition Deferred Tax Liabilities Equity Method Investments No definition available.
|
| X | ||||||||||
- Definition Deferred Tax Liabilities, Excluding Investment in Noncontrolled Affiliates, Net No definition available.
|
| X | ||||||||||
- Definition Deferred tax liabilities other regulatory assets. No definition available.
|
| X | ||||||||||
- Definition Deferred Tax Liabilities Pension And Other Postretirement Costs No definition available.
|
| X | ||||||||||
- Definition Deferred Tax Liabilities, Regulatory Assets, Future Income Tax No definition available.
|
| X | ||||||||||
- Definition Deferred tax liabilities storm costs. No definition available.
|
| X | ||||||||||
- Definition Regulatory Assets [Abstract] No definition available.
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from investments in unconsolidated subsidiaries and investments in other affiliates which are not controlled nor consolidated. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
|
Income Tax - Schedule of Income Tax Reconciliation (Details) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| STATUTORY TAX RATE | |||
| Federal | 35.00% | 35.00% | 35.00% |
| Changes in computed taxes resulting from: | |||
| State income tax | 4.00% | 4.00% | 5.00% |
| Cost of removal | 1.00% | (1.00%) | (5.00%) |
| Other plant-related items | (1.00%) | 0.00% | 0.00% |
| TCJA tax rate reduction | (13.00%) | 0.00% | 0.00% |
| Renewable energy credits | (1.00%) | (1.00%) | (1.00%) |
| Research and development credits | (0.00%) | (1.00%) | (0.00%) |
| Other | (2.00%) | 0.00% | 0.00% |
| Effective tax rate | 23.00% | 36.00% | 34.00% |
| CECONY | |||
| STATUTORY TAX RATE | |||
| Federal | 35.00% | 35.00% | 35.00% |
| Changes in computed taxes resulting from: | |||
| State income tax | 4.00% | 4.00% | 5.00% |
| Cost of removal | 1.00% | (1.00%) | (5.00%) |
| Other plant-related items | (1.00%) | (1.00%) | 0.00% |
| TCJA tax rate reduction | 0.00% | 0.00% | 0.00% |
| Renewable energy credits | (0.00%) | (0.00%) | (0.00%) |
| Research and development credits | (0.00%) | (1.00%) | (0.00%) |
| Other | (1.00%) | 0.00% | 0.00% |
| Effective tax rate | 38.00% | 36.00% | 35.00% |
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation, cost of removal No definition available.
|
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation, Other Plant-Related Items, Percent No definition available.
|
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation, Tax Credit, Renewable Energy Credits, Percent No definition available.
|
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Percent No definition available.
|
| X | ||||||||||
- Definition Federal Statutory Income Tax Rate [Abstract] No definition available.
|
| X | ||||||||||
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to research tax credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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|
Income Tax - Additional Information (Details) - USD ($) |
1 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Feb. 29, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in net deferred tax liabilities resulting from TCJA | $ 5,312,000,000 | |||
| Change in net income resulting from TCJA | 259,000,000 | |||
| Operating loss carryforwards, accelerated bonus depreciation | 19,000,000 | |||
| Deferred tax asset, valuation allowance | 33,000,000 | $ 16,000,000 | ||
| Deferred tax assets, charitable contribution carryforwards | 4,000,000 | 5,000,000 | $ 5,000,000 | |
| Income tax refund | $ 160,000,000 | |||
| Decrease in uncertain tax positions resulting from settlement of claims filed in previous years | 6,000,000 | 0 | 0 | |
| Effective income tax rate reconciliation, uncertainty of taxes | 8,000,000 | |||
| Effective income tax rate reconciliation, uncertainty net of federal taxes | 7,000,000 | |||
| Penalties for uncertain tax positions | 0 | 0 | 0 | |
| Amount of interest and penalties in their consolidated balance sheets | 0 | 0 | ||
| Unrecognized tax benefits that would have an impact on effective tax rate | 12,000,000 | |||
| Unrecognized tax benefits that would have an impact on effective tax rate, net of taxes | 11,000,000 | |||
| Charitable Contribution | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Deferred tax asset, valuation allowance | 3,000,000 | |||
| New York State | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in effective tax rate resulting from tax settlement | 6,000,000 | |||
| General Business Tax Credit | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Operating loss carryforwards | 176,000,000 | |||
| Renewable Energy Tax Credits | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Valuation allowance | 658,000,000 | |||
| Tax credit carryforward, valuation allowance | 0 | |||
| Charitable Contribution | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Tax credit carryforward, valuation allowance | 0 | 0 | 0 | |
| Federal | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Operating loss carryforwards | 121,000,000 | |||
| Federal | Carryback to 2007 and 2014 | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Operating loss carryforwards | 53,000,000 | |||
| Federal | Year 2036 | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Operating loss carryforwards | 68,000,000 | |||
| State | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Deferred tax asset, valuation allowance | 12,000,000 | |||
| State | New York State | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Operating loss carryforwards | 137,000,000 | |||
| Decrease in uncertain tax positions resulting from settlement of claims filed in previous years | 30,000,000 | |||
| Decrease in effective tax rate resulting from tax settlement, net of taxes | 4,000,000 | |||
| New York City | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Deferred tax asset, valuation allowance | 21,000,000 | |||
| Parent Company | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Change in net income resulting from TCJA | (21,000,000) | |||
| Clean Energy Businesses | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Change in net income resulting from TCJA | 269,000,000 | |||
| Con Edison Transmission | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Change in net income resulting from TCJA | 11,000,000 | |||
| Future Income Tax | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Increase in regulatory liability resulting from TCJA | 3,713,000,000 | |||
| Accelerated Tax Depreciation Benefits | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Increase in regulatory liability resulting from TCJA | 2,684,000,000 | |||
| Future Income Tax | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in regulatory asset resulting from TCJA | 1,250,000,000 | |||
| Revenue Taxes | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in regulatory asset resulting from TCJA | 90,000,000 | |||
| CECONY | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in net deferred tax liabilities resulting from TCJA | 4,781,000,000 | |||
| Deferred tax asset, valuation allowance | 0 | 0 | ||
| Income tax refund | $ 143,000,000 | |||
| Decrease in uncertain tax positions resulting from settlement of claims filed in previous years | 0 | $ 0 | $ 0 | |
| Effective income tax rate reconciliation, uncertainty of taxes | 4,000,000 | |||
| Unrecognized tax benefits that would have an impact on effective tax rate | 5,000,000 | |||
| CECONY | New York State | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in effective tax rate resulting from tax settlement | 18,000,000 | |||
| CECONY | State | New York State | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in effective tax rate resulting from tax settlement, net of taxes | 12,000,000 | |||
| CECONY | Future Income Tax | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Increase in regulatory liability resulting from TCJA | 3,513,000,000 | |||
| CECONY | Accelerated Tax Depreciation Benefits | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Increase in regulatory liability resulting from TCJA | 2,542,000,000 | |||
| CECONY | Future Income Tax | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in regulatory asset resulting from TCJA | 1,182,000,000 | |||
| CECONY | Revenue Taxes | ||||
| Operating Loss Carryforwards [Line Items] | ||||
| Decrease in regulatory asset resulting from TCJA | $ 86,000,000 | |||
| X | ||||||||||
- Definition Deferred Tax Assets, Operating Loss Carryforwards, Accelerated Bonus Depreciation No definition available.
|
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation, Tax Settlement, State and Local, Amount, Net of Taxes No definition available.
|
| X | ||||||||||
- Definition Income tax reconciliation tax contingencies net of federal taxes. No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Deferred Income Tax Liabilities, Net, Income Tax (Expense) Benefit No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Regulatory Assets, Income Tax Expense (Benefit) No definition available.
|
| X | ||||||||||
- Definition Tax Cuts And Jobs Act Of 2017, Change In Tax Rate, Regulatory Liabilities, Income Tax (Expense) Benefit No definition available.
|
| X | ||||||||||
- Definition Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Income Tax Expense (Benefit) No definition available.
|
| X | ||||||||||
- Definition Unrecognized Tax Benefits that Would Impact Effective Tax Rate, Net of Taxes No definition available.
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible charitable contribution carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible general business tax credit carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of estimated penalties accrued as of the balance sheet date arising from income tax examinations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in income tax contingencies. Including, but not limited to, domestic tax contingency, foreign tax contingency, state and local tax contingency, and other contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state and local income tax settlement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The amount of cash received during the period as refunds for the overpayment of taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from tax credit carryforwards for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of expense for penalties related to a tax position claimed or expected to be claimed in the tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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| X | ||||||||||
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|
Income Tax - Summary of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Balance at beginning of period | $ 42 | $ 34 | $ 34 |
| Additions based on tax positions related to the current year | 1 | 2 | 0 |
| Additions based on tax positions of prior years | 1 | 19 | 1 |
| Reductions for tax positions of prior years | (24) | (13) | 0 |
| Reductions from expiration of statute of limitations | (2) | 0 | (1) |
| Settlements | (6) | 0 | 0 |
| Balance at end of period | 12 | 42 | 34 |
| CECONY | |||
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Balance at beginning of period | 21 | 2 | 2 |
| Additions based on tax positions related to the current year | 1 | 2 | 0 |
| Additions based on tax positions of prior years | 1 | 19 | 0 |
| Reductions for tax positions of prior years | (18) | (2) | 0 |
| Reductions from expiration of statute of limitations | 0 | 0 | 0 |
| Settlements | 0 | 0 | 0 |
| Balance at end of period | $ 5 | $ 21 | $ 2 |
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
|
Stock-Based Compensation - Additional Information (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Options exercised | $ 0 | $ 2,000,000 | |
| Cash received by Con Edison for payment of exercise price | 3,000,000 | ||
| Income tax benefit realized from stock options exercised | 25,000,000 | 20,000,000 | $ 14,000,000 |
| Maximum employer contribution match (up to) | 1 | ||
| Amount employee contribution for employer match | 9 | ||
| Maximum employee investment per year (up to) | $ 25,000 | ||
| Maximum percentage allowed to invest (not more than) | 20.00% | ||
| CECONY | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Options exercised | 2,000,000 | ||
| Cash received by Con Edison for payment of exercise price | 3,000,000 | ||
| Income tax benefit realized from stock options exercised | $ 22,000,000 | 18,000,000 | 12,000,000 |
| Stock Options | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Award vesting period (years) | 3 years | ||
| Income tax benefit realized from stock options exercised | $ 1,000,000 | $ 1,000,000 | |
| Stock Options | Maximum | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Award expiration period (years) | 10 years | ||
| Performance RSUs | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Common stock received upon vesting (shares) | 1 | ||
| Compensation expense to be recognized | $ 38,000,000 | ||
| Nonvested awards, compensation cost not yet recognized, period for recognition (years) | 1 year | ||
| Performance RSUs | CECONY | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Compensation expense to be recognized | $ 31,000,000 | ||
| Nonvested awards, compensation cost not yet recognized, period for recognition (years) | 1 year | ||
| Restricted Stock Units | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Award vesting period (years) | 3 years | ||
| Time-based Awards | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Compensation expense to be recognized | $ 2,000,000 | ||
| Nonvested awards, compensation cost not yet recognized, period for recognition (years) | 1 year | ||
| Weighted average grant date price per share (in dollars per share) | $ 77.66 | ||
| Time-based Awards | CECONY | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Compensation expense to be recognized | $ 2,000,000 | ||
| Nonvested awards, compensation cost not yet recognized, period for recognition (years) | 1 year | ||
| Weighted average grant date price per share (in dollars per share) | $ 77.66 | ||
| 2013 LTIP | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Number of shares of common stock that can be awarded under the plan | 5,000,000 | ||
| TSR Portion | Performance RSUs | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Adjustment percentage used for Performance awards | 50.00% | ||
| Factor used for adjustment of Performance awards, low end (percent) | 0.00% | ||
| Factor used for adjustment of Performance awards, high end (percent) | 200.00% | ||
| Weighted average grant date price per share (in dollars per share) | $ 73.13 | ||
| TSR Portion | Performance RSUs | CECONY | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Weighted average grant date price per share (in dollars per share) | $ 72.78 | ||
| Non-TSR Portion | Performance RSUs | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Adjustment percentage used for Performance awards | 50.00% | ||
| Factor used for adjustment of Performance awards, low end (percent) | 0.00% | ||
| Factor used for adjustment of Performance awards, high end (percent) | 200.00% | ||
| Weighted average grant date price per share (in dollars per share) | $ 74.54 | ||
| Non-TSR Portion | Performance RSUs | CECONY | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Weighted average grant date price per share (in dollars per share) | $ 74.72 | ||
| LTIP | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Number of units issued (in shares) | 28,100 | ||
| Weighted average grant date price per share (in dollars per share) | $ 81.15 | ||
| Stock Purchase Plan | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Shares purchased on the open market | 719,125 | 720,268 | 761,784 |
| Weighted average share price per share, on shares purchased on open market (in dollars per share) | $ 79.57 | $ 72.67 | $ 62.75 |
| X | ||||||||||
- Definition Share-based Compensation Arrangement by Share-based Payment Award, contribution amount by employee for matching No definition available.
|
| X | ||||||||||
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Maximum employee contribution per year No definition available.
|
| X | ||||||||||
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Maximum employer contribution No definition available.
|
| X | ||||||||||
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Performance RSU's, adjustment percentage No definition available.
|
| X | ||||||||||
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Performance RSU's, Factor used, high range No definition available.
|
| X | ||||||||||
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Performance RSU's, Factor used, low range No definition available.
|
| X | ||||||||||
- Definition Share Based Compensation Arrangement By Share Based Payment Award Stock Options Expiration Period No definition available.
|
| X | ||||||||||
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Shares No definition available.
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| X | ||||||||||
- Definition Number of shares issued pursuant to the terms of a deferred compensation arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The weighted average of per share prices paid for shares purchased on the open market for issuance to employees under the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The number of shares purchased on the open market during the period for issuance to employees under the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | $ 63 | $ 50 | $ 34 |
| Income tax benefit | 25 | 20 | 14 |
| Performance-based restricted stock | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 53 | 42 | 27 |
| Time-based restricted stock | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 2 | 2 | 1 |
| Non-employee director deferred stock compensation | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 2 | 2 | 2 |
| Stock purchase plan | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 6 | 4 | 4 |
| CECONY | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 55 | 44 | 29 |
| Income tax benefit | 22 | 18 | 12 |
| CECONY | Performance-based restricted stock | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 45 | 36 | 23 |
| CECONY | Time-based restricted stock | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 2 | 2 | 1 |
| CECONY | Non-employee director deferred stock compensation | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | 2 | 2 | 2 |
| CECONY | Stock purchase plan | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Stock-based compensation expense | $ 6 | $ 4 | $ 3 |
| X | ||||||||||
- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Stock-Based Compensation - Assumptions Used to Calculate Fair Value (Details) - Performance RSUs |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Risk-free interest rate, minimum | 1.76% | 0.85% | 0.64% |
| Risk-free interest rate, maximum | 1.89% | 1.20% | 3.28% |
| Expected term (years) | 3 years | 3 years | 3 years |
| Expected share price volatility, minimum (percent) | 11.01% | 17.72% | |
| Expected share price volatility, maximum (percent) | 14.70% | 18.22% | |
| Expected share price volatility (percent) | 15.82% | ||
| X | ||||||||||
- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. No definition available.
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| X | ||||||||||
- Definition The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. No definition available.
|
| X | ||||||||||
- Definition The maximum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
|
| X | ||||||||||
- Definition The minimum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Stock-Based Compensation - Summary of Changes in Status of Performance RSUs' (Details) - Performance RSUs |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
$ / shares
shares
| |
| Units | |
| Non-vested at beginning of period (in shares) | shares | 1,087,137 |
| Granted (in shares) | shares | 368,150 |
| Vested (in shares) | shares | (375,684) |
| Forfeited (in shares) | shares | (50,671) |
| Transferred (in shares) | shares | 0 |
| Non-vested at end of period (in shares) | shares | 1,028,932 |
| CECONY | |
| Units | |
| Non-vested at beginning of period (in shares) | shares | 848,342 |
| Granted (in shares) | shares | 277,318 |
| Vested (in shares) | shares | (293,842) |
| Forfeited (in shares) | shares | (46,226) |
| Transferred (in shares) | shares | (1,426) |
| Non-vested at end of period (in shares) | shares | 784,166 |
| TSR Portion | |
| Weighted Average Grant Date Fair Value | |
| Non-vested at beginning of period (in dollars per share) | $ 55.45 |
| Granted (in dollars per share) | 73.13 |
| Vested (in dollars per share) | 25.36 |
| Forfeited (in dollars per share) | 76.29 |
| Transferred (in dollars per share) | 0.00 |
| Non-vested at end of period (in dollars per share) | $ 71.74 |
| Adjustment percentage used for Performance awards | 50.00% |
| TSR Portion | CECONY | |
| Weighted Average Grant Date Fair Value | |
| Non-vested at beginning of period (in dollars per share) | $ 54.92 |
| Granted (in dollars per share) | 72.78 |
| Vested (in dollars per share) | 25.32 |
| Forfeited (in dollars per share) | 76.41 |
| Transferred (in dollars per share) | 53.01 |
| Non-vested at end of period (in dollars per share) | 71.06 |
| Non-TSR Portion | |
| Weighted Average Grant Date Fair Value | |
| Non-vested at beginning of period (in dollars per share) | 63.03 |
| Granted (in dollars per share) | 74.54 |
| Vested (in dollars per share) | 53.66 |
| Forfeited (in dollars per share) | 72.23 |
| Transferred (in dollars per share) | 0.00 |
| Non-vested at end of period (in dollars per share) | $ 70.11 |
| Adjustment percentage used for Performance awards | 50.00% |
| Non-TSR Portion | CECONY | |
| Weighted Average Grant Date Fair Value | |
| Non-vested at beginning of period (in dollars per share) | $ 63.00 |
| Granted (in dollars per share) | 74.72 |
| Vested (in dollars per share) | 53.66 |
| Forfeited (in dollars per share) | 72.31 |
| Transferred (in dollars per share) | 72.52 |
| Non-vested at end of period (in dollars per share) | $ 70.08 |
| X | ||||||||||
- Definition Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Transferred In Period No definition available.
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- Definition Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Transfers, Weighted Average Grant Date Fair Value No definition available.
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- Definition Share Based Compensation Arrangement Percentage of RSU No definition available.
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| X | ||||||||||
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Stock-Based Compensation - Summary of Changes in Status of Time-Based Awards (Details) - Time-based Awards |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
$ / shares
shares
| |
| Units | |
| Non-vested at beginning of period (in shares) | shares | 65,980 |
| Granted (in shares) | shares | 23,000 |
| Vested (in shares) | shares | (21,359) |
| Forfeited (in shares) | shares | (2,751) |
| Non-vested at end of period (in shares) | shares | 64,870 |
| Weighted Average Grant Date Fair Value | |
| Non-vested at beginning of period (in dollars per share) | $ / shares | $ 64.04 |
| Granted (in dollars per share) | $ / shares | 77.66 |
| Vested (in dollars per share) | $ / shares | 53.77 |
| Forfeited (in dollars per share) | $ / shares | 71.62 |
| Non-vested at end of period (in dollars per share) | $ / shares | $ 71.93 |
| CECONY | |
| Units | |
| Non-vested at beginning of period (in shares) | shares | 62,580 |
| Granted (in shares) | shares | 21,800 |
| Vested (in shares) | shares | (20,359) |
| Forfeited (in shares) | shares | (2,601) |
| Non-vested at end of period (in shares) | shares | 61,420 |
| Weighted Average Grant Date Fair Value | |
| Non-vested at beginning of period (in dollars per share) | $ / shares | $ 64.03 |
| Granted (in dollars per share) | $ / shares | 77.66 |
| Vested (in dollars per share) | $ / shares | 53.77 |
| Forfeited (in dollars per share) | $ / shares | 71.93 |
| Non-vested at end of period (in dollars per share) | $ / shares | $ 71.93 |
| X | ||||||||||
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Financial Information by Business Segment (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Segment Reporting Information [Line Items] | |||
| Revenues | $ 12,033 | $ 12,075 | $ 12,554 |
| Depreciation and amortization | 1,341 | 1,216 | 1,130 |
| Operating income | 2,610 | 2,575 | 2,427 |
| Other Income (deductions) | 116 | 64 | 24 |
| Interest charges | 729 | 696 | 653 |
| Income taxes on operating income | 459 | 714 | 644 |
| Total assets | 48,111 | 48,255 | 45,642 |
| Capital expenditures | 3,606 | 5,235 | 3,418 |
| Income taxes on non-operating income | $ 13 | $ (16) | $ (40) |
| Corporate income tax rate | 35.00% | 35.00% | 35.00% |
| Federal income tax expense | $ 259 | ||
| Parent Company | |||
| Segment Reporting Information [Line Items] | |||
| Interest charges | 50 | $ 41 | $ 29 |
| Total assets | 17,231 | 16,192 | |
| Federal income tax expense | (21) | ||
| Clean Energy Businesses | |||
| Segment Reporting Information [Line Items] | |||
| Federal income tax expense | 269 | ||
| Con Edison Transmission | |||
| Segment Reporting Information [Line Items] | |||
| Federal income tax expense | 11 | ||
| CECONY | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 10,468 | 10,165 | 10,328 |
| Depreciation and amortization | 1,195 | 1,106 | 1,040 |
| Operating income | 2,405 | 2,262 | 2,247 |
| Other Income (deductions) | 7 | 0 | (5) |
| Interest charges | 623 | 603 | 584 |
| Total assets | 40,451 | 40,856 | |
| Income taxes on non-operating income | $ (3) | $ (14) | $ (14) |
| Corporate income tax rate | 35.00% | 35.00% | 35.00% |
| Operating segment | Clean Energy Businesses | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | $ 694 | $ 1,091 | $ 1,383 |
| Depreciation and amortization | 74 | 42 | 22 |
| Operating income | 69 | 183 | 58 |
| Other Income (deductions) | 33 | 21 | 35 |
| Interest charges | 43 | 34 | 11 |
| Income taxes on operating income | (273) | 53 | 22 |
| Total assets | 2,735 | 2,551 | 1,680 |
| Capital expenditures | 447 | 1,235 | 823 |
| Operating segment | Con Edison Transmission | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 2 | 0 | 0 |
| Depreciation and amortization | 1 | 0 | 0 |
| Operating income | (8) | (3) | 0 |
| Other Income (deductions) | 80 | 43 | 0 |
| Interest charges | 16 | 6 | 0 |
| Income taxes on operating income | (11) | 0 | 0 |
| Total assets | 1,222 | 1,150 | 3 |
| Capital expenditures | 66 | 1,078 | 0 |
| Operating segment | CECONY | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 10,468 | 10,165 | 10,328 |
| Depreciation and amortization | 1,195 | 1,106 | 1,040 |
| Operating income | 2,405 | 2,262 | 2,247 |
| Other Income (deductions) | 7 | 0 | (5) |
| Interest charges | 623 | 603 | 584 |
| Income taxes on operating income | 688 | 617 | 588 |
| Total assets | 40,451 | 40,856 | 40,230 |
| Capital expenditures | 2,904 | 2,756 | 2,435 |
| Operating segment | CECONY | Electric | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 7,972 | 8,106 | 8,172 |
| Depreciation and amortization | 925 | 865 | 820 |
| Operating income | 1,862 | 1,847 | 1,798 |
| Other Income (deductions) | 7 | 2 | (2) |
| Interest charges | 472 | 459 | 447 |
| Income taxes on operating income | 511 | 495 | 447 |
| Total assets | 29,661 | 30,708 | 30,603 |
| Capital expenditures | 1,905 | 1,819 | 1,658 |
| Operating segment | CECONY | Gas | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 1,901 | 1,508 | 1,527 |
| Depreciation and amortization | 185 | 159 | 142 |
| Operating income | 472 | 357 | 356 |
| Other Income (deductions) | 0 | (1) | (2) |
| Interest charges | 113 | 105 | 96 |
| Income taxes on operating income | 152 | 92 | 100 |
| Total assets | 8,387 | 7,553 | 6,974 |
| Capital expenditures | 909 | 811 | 671 |
| Operating segment | CECONY | Steam | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 595 | 551 | 629 |
| Depreciation and amortization | 85 | 82 | 78 |
| Operating income | 71 | 58 | 93 |
| Other Income (deductions) | 0 | (1) | (1) |
| Interest charges | 38 | 39 | 41 |
| Income taxes on operating income | 25 | 30 | 41 |
| Total assets | 2,403 | 2,595 | 2,653 |
| Capital expenditures | 90 | 126 | 106 |
| Operating segment | O&R | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 874 | 821 | 845 |
| Depreciation and amortization | 71 | 67 | 68 |
| Operating income | 141 | 130 | 121 |
| Other Income (deductions) | 1 | 1 | (4) |
| Interest charges | 36 | 36 | 35 |
| Income taxes on operating income | 42 | 40 | 33 |
| Total assets | 2,773 | 2,758 | 2,719 |
| Capital expenditures | 189 | 166 | 160 |
| Operating segment | O&R | Electric | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 642 | 637 | 663 |
| Depreciation and amortization | 51 | 49 | 50 |
| Operating income | 100 | 95 | 103 |
| Other Income (deductions) | 1 | 1 | (2) |
| Interest charges | 24 | 24 | 23 |
| Income taxes on operating income | 30 | 30 | 31 |
| Total assets | 1,949 | 1,949 | 2,140 |
| Capital expenditures | 128 | 114 | 114 |
| Operating segment | O&R | Gas | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 232 | 184 | 182 |
| Depreciation and amortization | 20 | 18 | 18 |
| Operating income | 41 | 35 | 18 |
| Other Income (deductions) | 0 | 0 | (2) |
| Interest charges | 12 | 12 | 12 |
| Income taxes on operating income | 12 | 10 | 2 |
| Total assets | 824 | 809 | 579 |
| Capital expenditures | 61 | 52 | 46 |
| Other | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | (5) | (2) | (2) |
| Depreciation and amortization | 0 | 1 | 0 |
| Operating income | 3 | 3 | 1 |
| Other Income (deductions) | (5) | (1) | (2) |
| Interest charges | 11 | 17 | 23 |
| Income taxes on operating income | 13 | 4 | 1 |
| Total assets | 930 | 940 | 1,010 |
| Capital expenditures | 0 | 0 | 0 |
| Other | O&R | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 0 | 0 | 0 |
| Depreciation and amortization | 0 | 0 | 0 |
| Operating income | 0 | 0 | 0 |
| Other Income (deductions) | 0 | 0 | 0 |
| Interest charges | 0 | 0 | 0 |
| Income taxes on operating income | 0 | 0 | 0 |
| Total assets | 0 | 0 | 0 |
| Capital expenditures | 0 | 0 | 0 |
| Inter-segment | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 0 | (7) | 2 |
| Inter-segment | Clean Energy Businesses | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 0 | 7 | (2) |
| Inter-segment | CECONY | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | (97) | (111) | (110) |
| Inter-segment | CECONY | Electric | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 16 | 17 | 18 |
| Inter-segment | CECONY | Gas | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | 6 | 6 | 6 |
| Inter-segment | CECONY | Steam | |||
| Segment Reporting Information [Line Items] | |||
| Revenues | $ 75 | $ 88 | $ 86 |
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- Definition Income tax (benefit) applicable to non-operating income. No definition available.
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- Definition Operating Income Tax Expense Benefit No definition available.
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- Definition Tax Cuts and Jobs Act of 2017, Income Tax Expense (Benefit) No definition available.
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- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The aggregate costs related to construction and development services during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Derivative Instruments and Hedging Activities - Fair Values of Commodity Derivatives Including Offsetting of Assets and Liabilities (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Fair value of derivative assets | ||
| Net Amounts of Assets/ (Liabilities) | $ 453 | $ 363 |
| Fair value of derivative liabilities | ||
| Net Amounts of Assets/ (Liabilities) | (55) | (117) |
| Net fair value derivative assets/(liabilities) | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (17) | (99) |
| Gross Amounts Offset | 0 | 6 |
| Net Amounts of Assets/ (Liabilities) | (17) | (93) |
| Margin deposits | 12 | 7 |
| Interest Rate Swap | ||
| Fair value of derivative liabilities | ||
| Net Amounts of Assets/ (Liabilities) | (1) | (1) |
| CECONY | ||
| Fair value of derivative assets | ||
| Net Amounts of Assets/ (Liabilities) | 414 | 326 |
| Net fair value derivative assets/(liabilities) | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (14) | (95) |
| Gross Amounts Offset | (1) | 9 |
| Net Amounts of Assets/ (Liabilities) | (15) | (86) |
| Margin deposits | 11 | 7 |
| Fair Value of Derivative Liabilities, Current | ||
| Fair value of derivative liabilities | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (67) | (138) |
| Gross Amounts Offset | 50 | 61 |
| Net Amounts of Assets/ (Liabilities) | (17) | (77) |
| Fair Value of Derivative Liabilities, Current | CECONY | ||
| Fair value of derivative liabilities | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (26) | (111) |
| Gross Amounts Offset | 14 | 45 |
| Net Amounts of Assets/ (Liabilities) | (12) | (66) |
| Fair Value of Derivative Liabilities, Non-current | ||
| Fair value of derivative liabilities | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (43) | (91) |
| Gross Amounts Offset | 5 | 52 |
| Net Amounts of Assets/ (Liabilities) | (38) | (39) |
| Fair Value of Derivative Liabilities, Non-current | CECONY | ||
| Fair value of derivative liabilities | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (36) | (77) |
| Gross Amounts Offset | 4 | 44 |
| Net Amounts of Assets/ (Liabilities) | (32) | (33) |
| Fair Value of Derivative Liabilities | ||
| Fair value of derivative liabilities | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (110) | (229) |
| Gross Amounts Offset | 55 | 113 |
| Net Amounts of Assets/ (Liabilities) | (55) | (116) |
| Fair Value of Derivative Liabilities | CECONY | ||
| Fair value of derivative liabilities | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | (62) | (188) |
| Gross Amounts Offset | 18 | 89 |
| Net Amounts of Assets/ (Liabilities) | (44) | (99) |
| Fair Value of Derivative Assets, Current | ||
| Fair value of derivative assets | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | 83 | 81 |
| Gross Amounts Offset | (51) | (64) |
| Net Amounts of Assets/ (Liabilities) | 32 | 17 |
| Fair Value of Derivative Assets, Current | CECONY | ||
| Fair value of derivative assets | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | 39 | 52 |
| Gross Amounts Offset | (15) | (45) |
| Net Amounts of Assets/ (Liabilities) | 24 | 7 |
| Fair Value of Derivative Assets, Non-current | ||
| Fair value of derivative assets | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | 10 | 49 |
| Gross Amounts Offset | (4) | (43) |
| Net Amounts of Assets/ (Liabilities) | 6 | 6 |
| Fair Value of Derivative Assets, Non-current | CECONY | ||
| Fair value of derivative assets | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | 9 | 41 |
| Gross Amounts Offset | (4) | (35) |
| Net Amounts of Assets/ (Liabilities) | 5 | 6 |
| Fair Value of Derivative Assets | ||
| Fair value of derivative assets | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | 93 | 130 |
| Gross Amounts Offset | (55) | (107) |
| Net Amounts of Assets/ (Liabilities) | 38 | 23 |
| Fair Value of Derivative Assets | CECONY | ||
| Fair value of derivative assets | ||
| Gross Amounts of Recognized Assets/ (Liabilities) | 48 | 93 |
| Gross Amounts Offset | (19) | (80) |
| Net Amounts of Assets/ (Liabilities) | $ 29 | $ 13 |
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- Definition Derivative Asset (Liability), Gross Amount Offset in Balance Sheet No definition available.
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- Definition Offsetting Derivative Assets and Liabilities [Abstract] No definition available.
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- Definition Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Derivative Instruments and Hedging Activities - Realized and Unrealized Gains or Losses on Commodity Derivatives (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | $ 3 | $ 24 |
| Total deferred gains/(losses) | (99) | (188) |
| Net deferred gains/(losses) | (96) | (164) |
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 8 | (203) |
| Purchased power expense | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 0 | (101) |
| Unrealized gain/(loss) on derivatives | 11 | |
| Gas purchased for resale | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 3 | (112) |
| Non-utility revenue | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 5 | 9 |
| Other operations and maintenance expense | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 0 | 1 |
| Unrealized gain/(loss) on derivatives | 1 | |
| Non-utility operating revenue | ||
| Pre-tax gain/(loss) recognized in income | ||
| Unrealized gain/(loss) on derivatives | (5) | |
| Deferred Derivative Gains,Current | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 3 | 23 |
| Deferred Derivative Gains, Noncurrent | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 0 | 1 |
| Deferred Derivative Losses, Current | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 51 | 22 |
| Recoverable Energy Costs, Current | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | (154) | (212) |
| Deferred Derivative Losses, Noncurrent | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 4 | 2 |
| CECONY | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 4 | 20 |
| Total deferred gains/(losses) | (90) | (172) |
| Net deferred gains/(losses) | (86) | (152) |
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 0 | 1 |
| CECONY | Purchased power expense | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 0 | 0 |
| CECONY | Gas purchased for resale | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 0 | 0 |
| CECONY | Non-utility revenue | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 0 | 0 |
| CECONY | Other operations and maintenance expense | ||
| Pre-tax gain/(loss) recognized in income | ||
| Total pre-tax gain/(loss) recognized in income | 0 | 1 |
| Unrealized gain/(loss) on derivatives | 1 | |
| CECONY | Deferred Derivative Gains,Current | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 4 | 18 |
| CECONY | Deferred Derivative Gains, Noncurrent | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 0 | 2 |
| CECONY | Deferred Derivative Losses, Current | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | 49 | 18 |
| CECONY | Recoverable Energy Costs, Current | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | (144) | (194) |
| CECONY | Deferred Derivative Losses, Noncurrent | ||
| Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations: | ||
| Total deferred gains/(losses) | $ 5 | $ 4 |
| X | ||||||||||
- Definition Deferred Derivative Gains Losses No definition available.
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- Definition Deferred gain/(loss), liability No definition available.
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- Definition Derivative Assets Liabilities At Fair Value By Balance Sheet Classification [Abstract] No definition available.
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- Definition Net deferred gain/(loss) No definition available.
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- Definition Pretax Effects Of Derivative Instruments On Consolidated Statements Of Operations [Abstract] No definition available.
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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details) gal in Thousands |
Dec. 31, 2017
MW
MMBTU
gal
MWh
|
|---|---|
| Electric Energy | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | MWh | 31,741,652 |
| Capacity | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | MW | 10,275 |
| Natural Gas | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | MMBTU | 177,433,144 |
| Refined Fuels | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | gal | 3,780 |
| CECONY | Electric Energy | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | MWh | 29,696,600 |
| CECONY | Capacity | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | MW | 5,100 |
| CECONY | Natural Gas | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | MMBTU | 169,790,000 |
| CECONY | Refined Fuels | |
| Derivatives, Fair Value [Line Items] | |
| Notional amount | gal | 3,780 |
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- Definition Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Derivative Instruments and Hedging Activities - Additional Information (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Investment Holdings [Line Items] | ||
| Energy supply and hedging activities credit exposure total | $ 103 | |
| Makeup of net credit exposure with investment-grade counterparties | 39 | |
| Makeup of net credit exposure independent system operators | 29 | |
| Makeup of net credit exposure with commodity exchange brokers | 22 | |
| Makeup of net credit exposure non-investment grade/non-rated counterparties | 13 | |
| Derivative liabilities | 55 | $ 117 |
| Interest Rate Swap | ||
| Investment Holdings [Line Items] | ||
| Derivative liabilities | 1 | $ 1 |
| CECONY | ||
| Investment Holdings [Line Items] | ||
| Energy supply and hedging activities credit exposure total | 28 | |
| Makeup of net credit exposure with investment-grade counterparties | 17 | |
| Makeup of net credit exposure with commodity exchange brokers | 11 | |
| Clean Energy Businesses | Coram | Interest Rate Swap | ||
| Investment Holdings [Line Items] | ||
| Derivative, fixed interest rate | 2.0855% | |
| Derivative liabilities | $ 0 | $ 1 |
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- Definition Credit Exposure Independent System Operators No definition available.
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- Definition Credit exposure nonrated counterparties No definition available.
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- Definition Maximum Potential Future Exposure On Credit Risk Derivatives With Commodity Exchange Brokers No definition available.
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- Definition Maximum Potential Future Exposure On Credit Risk Derivatives With Investment Grade Counterparties No definition available.
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- Definition Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fixed interest rate related to the interest rate derivative. No definition available.
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Derivative Instruments and Hedging Activities - Aggregate Fair Value of Companies' Derivative Instruments with Credit-Risk-Related Contingent Features (Details) $ in Millions |
Dec. 31, 2017
USD ($)
|
|---|---|
| Derivatives, Fair Value [Line Items] | |
| Aggregate fair value – net liabilities | $ 39 |
| Collateral posted | 68 |
| Downgrade One Level from Current Ratings | |
| Derivatives, Fair Value [Line Items] | |
| Additional collateral | 0 |
| Downgrade to Below Investment Grade from Current Ratings | |
| Derivatives, Fair Value [Line Items] | |
| Additional collateral | 29 |
| Derivatives in net asset position additional collateral | 18 |
| Additional Collateral Required Due To Loss Of Unsecured Credit | |
| Derivatives, Fair Value [Line Items] | |
| Collateral posted | 8 |
| CECONY | |
| Derivatives, Fair Value [Line Items] | |
| Aggregate fair value – net liabilities | 31 |
| Collateral posted | 63 |
| CECONY | Downgrade One Level from Current Ratings | |
| Derivatives, Fair Value [Line Items] | |
| Additional collateral | 0 |
| CECONY | Downgrade to Below Investment Grade from Current Ratings | |
| Derivatives, Fair Value [Line Items] | |
| Additional collateral | $ 22 |
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- Definition The additional collateral that would be required for derivative instruments that are net assets. No definition available.
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- Definition The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value of credit risk derivative asset after deduction of credit risk derivative liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | $ 453 | $ 363 |
| Derivative liabilities | 55 | 117 |
| CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 414 | 326 |
| Netting Adjustment | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | (39) | (24) |
| Derivative liabilities | (52) | (38) |
| Netting Adjustment | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | (7) | (10) |
| Level 1 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 288 | 236 |
| Derivative liabilities | 8 | 4 |
| Level 1 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 263 | 210 |
| Level 2 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 197 | 144 |
| Derivative liabilities | 93 | 145 |
| Level 2 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 154 | 125 |
| Level 3 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 7 | 7 |
| Derivative liabilities | 6 | 6 |
| Level 3 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 4 | 1 |
| Commodity | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 50 | 30 |
| Derivative liabilities | 55 | 116 |
| Derivative liabilities transferred from Level 3 to Level 2 | 11 | |
| Commodity | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 40 | 20 |
| Derivative liabilities | 44 | 99 |
| Derivative liabilities transferred from Level 3 to Level 2 | 10 | |
| Commodity | Netting Adjustment | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | (39) | (24) |
| Derivative liabilities | (52) | (38) |
| Commodity | Netting Adjustment | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | (7) | (10) |
| Derivative liabilities | (18) | (26) |
| Commodity | Level 1 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 5 | 14 |
| Derivative liabilities | 8 | 4 |
| Commodity | Level 1 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 3 | 10 |
| Derivative liabilities | 5 | 1 |
| Commodity | Level 2 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 77 | 33 |
| Derivative liabilities | 93 | 144 |
| Commodity | Level 2 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 40 | 19 |
| Derivative liabilities | 57 | 124 |
| Commodity | Level 3 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 7 | 7 |
| Derivative liabilities | 6 | 6 |
| Commodity | Level 3 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 4 | 1 |
| Derivative liabilities | 0 | 0 |
| Interest Rate Swap | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative liabilities | 1 | 1 |
| Interest Rate Swap | Netting Adjustment | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative liabilities | 0 | 0 |
| Interest Rate Swap | Level 1 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative liabilities | 0 | 0 |
| Interest Rate Swap | Level 2 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative liabilities | 1 | |
| Interest Rate Swap | Level 3 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative liabilities | 0 | 0 |
| Other | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 403 | 333 |
| Other | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 374 | 306 |
| Other | Netting Adjustment | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 0 | 0 |
| Other | Netting Adjustment | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 0 | 0 |
| Other | Level 1 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 283 | 222 |
| Other | Level 1 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 260 | 200 |
| Other | Level 2 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 120 | 111 |
| Other | Level 2 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 114 | 106 |
| Other | Level 3 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | 0 | 0 |
| Other | Level 3 | CECONY | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Derivative assets | $ 0 | $ 0 |
| X | ||||||||||
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair Value Measurements - Schedule of Commodity Derivatives (Details) - Level 3 $ in Millions |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2017
USD ($)
$ / MWh
$ / kWh
$ / kW-month
|
Sep. 30, 2017
USD ($)
|
|
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Fair Value of commodity derivatives | $ | $ 1 | |
| CECONY | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Fair Value of commodity derivatives | $ | $ 4 | |
| Electricity | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Fair Value of commodity derivatives | $ | $ (1) | |
| Electricity | CECONY | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Fair Value of commodity derivatives | $ | 3 | |
| Electricity | Forward Energy Prices | Minimum | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh | 15.52 | |
| Electricity | Forward Energy Prices | Maximum | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh | 115.00 | |
| Electricity | Forward Capacity Prices | Minimum | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per kW-month) | $ / kW-month | 1.50 | |
| Electricity | Forward Capacity Prices | Minimum | CECONY | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per kW-month) | $ / kWh | 2.35 | |
| Electricity | Forward Capacity Prices | Maximum | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per kW-month) | $ / kW-month | 12.50 | |
| Electricity | Forward Capacity Prices | Maximum | CECONY | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per kW-month) | $ / kWh | 12.50 | |
| Transmission Congestion Contracts | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Fair Value of commodity derivatives | $ | $ 2 | |
| Transmission Congestion Contracts | CECONY | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Fair Value of commodity derivatives | $ | $ 1 | |
| Transmission Congestion Contracts | Inter Zonal Forward Price Curves Adjusted for Historical Zonal Losses | Minimum | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh | 0.19 | |
| Transmission Congestion Contracts | Inter Zonal Forward Price Curves Adjusted for Historical Zonal Losses | Minimum | CECONY | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh | 0.51 | |
| Transmission Congestion Contracts | Inter Zonal Forward Price Curves Adjusted for Historical Zonal Losses | Maximum | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh | 3.57 | |
| Transmission Congestion Contracts | Inter Zonal Forward Price Curves Adjusted for Historical Zonal Losses | Maximum | CECONY | ||
| Fair Value, Concentration of Risk, Financial Statement Captions [Line Items] | ||
| Unobservable Inputs Range (dollar per MWh/Dt) | $ / MWh | 3.00 |
| X | ||||||||||
- Definition Commodity Contracts Derivatives Fair Value No definition available.
|
| X | ||||||||||
- Definition Fair Value Measurement With Unobservable Inputs Reconciliation Price No definition available.
|
| X | ||||||||||
- Definition Fair Value Measurements With Unobservable Inputs Reconciliation Recurring Basis Asset Foreign Exchange Gains Losses No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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Fair Value Measurements - Reconciliation of Beginning and Ending Net Balances for Assets and Liabilities Measured at Level 3 Fair Value (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
| Beginning Balance | $ 1 | $ 6 |
| Included in earnings | 8 | (7) |
| Included in regulatory assets and liabilities | (13) | (6) |
| Purchases | 2 | 4 |
| Sales | 0 | 4 |
| Settlements | (8) | 0 |
| Transfer out of level 3 | 11 | 0 |
| Ending Balance | 1 | 1 |
| CECONY | ||
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
| Beginning Balance | 1 | 8 |
| Included in earnings | 2 | (1) |
| Included in regulatory assets and liabilities | (7) | (6) |
| Purchases | 1 | 2 |
| Sales | 0 | 0 |
| Settlements | (3) | (2) |
| Transfer out of level 3 | 10 | 0 |
| Ending Balance | $ 4 | $ 1 |
| X | ||||||||||
- Definition Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Included In regulatory Assets And Liabilities No definition available.
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Non-utility revenue | ||
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair value, assets and liabilities measured on recurring basis, change in unrealized gain (loss) | $ 2 | $ 0 |
| Purchased power expense | ||
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Fair value, assets and liabilities measured on recurring basis, change in unrealized gain (loss) | 0 | (1) |
| Clean Energy Businesses | Non-utility revenue | ||
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Gain (loss) on Level 3 energy derivative assets and liabilities | 2 | 0 |
| Clean Energy Businesses | Purchased power expense | ||
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | ||
| Gain (loss) on Level 3 energy derivative assets and liabilities | $ 0 | $ (6) |
| X | ||||||||||
- Definition Amount of unrealized (holding) gain (loss) which is included in the statement of income (or changes in net assets) related to those assets still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Variable Interest Entities - Additional Information (Details) $ in Millions |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2017
USD ($)
MW
|
Dec. 31, 2016
USD ($)
|
|
| Variable Interest Entity [Line Items] | ||
| Noncontrolling interest | $ 7 | $ 8 |
| Noncontrolling Interest | ||
| Variable Interest Entity [Line Items] | ||
| Noncontrolling interest | $ 7 | 7 |
| Variable Interest Entity, Primary Beneficiary | Texas Solar 4 | ||
| Variable Interest Entity [Line Items] | ||
| Percentage of variable interests | 80.00% | |
| Generating capacity (MW AC) | MW | 40 | |
| VIE consolidated, carrying amount, assets and liabilities, net | $ 26 | $ 54 |
| Con Edison Development | Variable Interest Entity, Primary Beneficiary | Texas Solar 4 | ||
| Variable Interest Entity [Line Items] | ||
| Percentage of variable interests | 80.00% |
| X | ||||||||||
- Definition Generating Capacity No definition available.
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The net carrying amount of the consolidated Variable Interest Entity's assets and liabilities included in the reporting entity's statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Variable Interest Entities - Net Assets of Texas Solar 4 (Details) - Texas Solar 4 - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Business Acquisition [Line Items] | ||
| Restricted cash | $ 5 | $ 8 |
| Non-utility property, less accumulated depreciation of $12 and $9, respectively | 101 | 104 |
| Other assets | 8 | 43 |
| Total assets | 114 | 155 |
| Long-term debt due within one year | 2 | 3 |
| Other liabilities | 28 | 38 |
| Long-term debt | 58 | 60 |
| Total liabilities | 88 | 101 |
| Accumulated depreciation | $ 12 | $ 9 |
| X | ||||||||||
- Definition Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assume, Property, Plant, and Equipment, Property, Plant and Equipment, Non-Utility Plant, Depreciation No definition available.
|
| X | ||||||||||
- Definition Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assume, Property, Plant, and Equipment, Property, Plant and Equipment, Non-Utility Plant, Net No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Amount of assets acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt due within one year or within the normal operating cycle, if longer, assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of other liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of liabilities assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Variable Interest Entities - Summary of VIEs (Details) |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
USD ($)
MW
| |
| Variable Interest Entity, Not Primary Beneficiary | Copper Mountain Solar 3 | |
| Variable Interest Entity [Line Items] | |
| Generating Capacity Owned (MW AC) | MW | 128 |
| Power Purchase Agreement Term in Years | 20 years |
| Maximum Exposure to Loss | $ 175,000,000 |
| Variable Interest Entity, Not Primary Beneficiary | Mesquite Solar 1 | |
| Variable Interest Entity [Line Items] | |
| Generating Capacity Owned (MW AC) | MW | 83 |
| Power Purchase Agreement Term in Years | 20 years |
| Maximum Exposure to Loss | $ 103,000,000 |
| Variable Interest Entity, Not Primary Beneficiary | Copper Mountain Solar 2 | |
| Variable Interest Entity [Line Items] | |
| Generating Capacity Owned (MW AC) | MW | 75 |
| Power Purchase Agreement Term in Years | 25 years |
| Maximum Exposure to Loss | $ 82,000,000 |
| Variable Interest Entity, Not Primary Beneficiary | California Solar | |
| Variable Interest Entity [Line Items] | |
| Generating Capacity Owned (MW AC) | MW | 55 |
| Power Purchase Agreement Term in Years | 25 years |
| Maximum Exposure to Loss | $ 63,000,000 |
| Variable Interest Entity, Not Primary Beneficiary | Broken Bow II | |
| Variable Interest Entity [Line Items] | |
| Generating Capacity Owned (MW AC) | MW | 38 |
| Power Purchase Agreement Term in Years | 25 years |
| Maximum Exposure to Loss | $ 44,000,000 |
| Variable Interest Entity, Primary Beneficiary | Texas Solar 4 | |
| Variable Interest Entity [Line Items] | |
| Generating Capacity Owned (MW AC) | MW | 32 |
| Power Purchase Agreement Term in Years | 25 years |
| Maximum Exposure to Loss | $ 19,000,000 |
| Percentage of variable interests | 80.00% |
| Maximum exposure for consolidated investments | $ 7,000,000 |
| Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure | |
| Variable Interest Entity [Line Items] | |
| Percentage of variable interests | 50.00% |
| X | ||||||||||
- Definition Generating capacity of plant owned thru equity method investment in entity. No definition available.
|
| X | ||||||||||
- Definition Period covered by the long-term purchase commitment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
|
| X | ||||||||||
- Definition Difference between the carrying amount of assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the variable interest entity (VIE) and the reporting entity's maximum exposure to loss as a result of its involvement with the VIE, where the reporting entity is not the VIE's primary beneficiary. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Asset Retirement Obligations (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Regulatory Liabilities [Line Items] | ||
| Accrued liability - asset retirement obligations | $ 314 | $ 246 |
| Increase in liabilities for asset retirement obligations due to changes in estimated cash flows | 98 | |
| Asset retirement obligations, accretion expense | 10 | |
| Asset retirement obligations, liabilities settled | 40 | |
| Asset retirement obligations, reductions | 36 | 37 |
| CECONY | ||
| Regulatory Liabilities [Line Items] | ||
| Accrued liability - asset retirement obligations | 287 | 227 |
| Increase in liabilities for asset retirement obligations due to changes in estimated cash flows | 91 | |
| Asset retirement obligations, accretion expense | 9 | |
| Asset retirement obligations, liabilities settled | 40 | |
| Asset retirement obligations, reductions | $ 36 | $ 37 |
| X | ||||||||||
- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in asset retirement obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
Related Party Transactions - Summary of Costs of Administrative and Other Services Provided and Received (Details) - CECONY - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Related Party Transaction [Line Items] | |||
| Cost of services provided | $ 111 | $ 108 | $ 99 |
| Cost of services received | $ 64 | $ 64 | $ 60 |
| X | ||||||||||
- Definition Cost of services received. No definition available.
|
| X | ||||||||||
- Definition Total costs related to services rendered by an entity during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
Related Party Transactions - Additional Information (Details) |
7 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|
|
Dec. 31, 2016
USD ($)
|
Dec. 31, 2017
USD ($)
MMBTU
agreement
|
Dec. 31, 2016
USD ($)
|
Dec. 31, 2015
USD ($)
|
Nov. 30, 2016 |
Jan. 31, 2016 |
|
| Related Party Transaction [Line Items] | ||||||
| Gas purchased for resale | $ 808,000,000 | $ 477,000,000 | $ 495,000,000 | |||
| CECONY | ||||||
| Related Party Transaction [Line Items] | ||||||
| Sale of natural gas | 66,000,000 | 47,000,000 | 54,000,000 | |||
| Gas purchased for resale | 510,000,000 | 319,000,000 | $ 337,000,000 | |||
| Funding limit of CECONY to O&R (not to exceed) | $ 250,000,000 | |||||
| CECONY | Related Party, Lending of Funds | ||||||
| Related Party Transaction [Line Items] | ||||||
| Lending period (not more than) (months) | 12 months | |||||
| CECONY | Equity Method Investee | Mountain Valley Pipeline | ||||||
| Related Party Transaction [Line Items] | ||||||
| Transportation contract term | 20 years | |||||
| Generating capacity per day (in dekatherms) | MMBTU | 250,000 | |||||
| Amount of transaction | $ 0 | |||||
| CECONY | Equity Method Investee | Stagecoach | Purchased Power Costs | ||||||
| Related Party Transaction [Line Items] | ||||||
| Gas purchased for resale | $ 49,000,000 | |||||
| CECONY | Equity Method Investee | Stagecoach | Purchased Power Costs | Clean Energy Businesses | ||||||
| Related Party Transaction [Line Items] | ||||||
| Number of electricity sales agreements entered into | agreement | 2 | |||||
| CECONY | Affiliated Entity | Financial Electric Capacity Contract | Con Edison Energy | ||||||
| Related Party Transaction [Line Items] | ||||||
| Amount of transaction | $ 3,000,000 | 0 | ||||
| CET Electric | ||||||
| Related Party Transaction [Line Items] | ||||||
| Ownership interest, percentage | 45.70% | |||||
| CET Gas | Stagecoach | ||||||
| Related Party Transaction [Line Items] | ||||||
| Percentage of equity interest owned | 50.00% | |||||
| CET Gas | Mountain Valley Pipeline | ||||||
| Related Party Transaction [Line Items] | ||||||
| Percentage of equity interest owned | 12.50% | 12.50% | ||||
| O&R | ||||||
| Related Party Transaction [Line Items] | ||||||
| Outstanding loans to O&R | $ 0 | $ 0 | ||||
| X | ||||||||||
- Definition Generating Capacity Per Day No definition available.
|
| X | ||||||||||
- Definition Maximum Amount Of Funding No definition available.
|
| X | ||||||||||
- Definition Outstanding Loan No definition available.
|
| X | ||||||||||
- Definition Related Party Transaction, Lending Period No definition available.
|
| X | ||||||||||
- Definition Related Party Transaction, Number of Agreements No definition available.
|
| X | ||||||||||
- Definition Sales Of Natural Gas Propane Ngls And Condensate And Affiliates No definition available.
|
| X | ||||||||||
- Definition Term Of Contract No definition available.
|
| X | ||||||||||
- Definition Cost of oil and gas purchased during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. No definition available.
|
| X | ||||||||||
- Definition Amount of transactions with related party during the financial reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Texas Solar 7 (Details) - Texas Solar 7 $ in Millions |
1 Months Ended | 12 Months Ended | |
|---|---|---|---|
|
Jan. 31, 2016
USD ($)
MW
|
Dec. 31, 2016
USD ($)
|
Dec. 31, 2017
USD ($)
|
|
| Business Acquisition [Line Items] | |||
| Generating capacity (MW AC) | MW | 106 | ||
| Con Edison Development | |||
| Business Acquisition [Line Items] | |||
| Percentage of voting interest acquired | 100.00% | ||
| Payments to acquire business | $ 227 | ||
| Non-utility construction work in progress | 218 | ||
| Receivable from parent company | $ 9 | ||
| Net assets | $ 127 | $ 137 | |
| Intangible assets | $ 41 |
| X | ||||||||||
- Definition Generating Capacity No definition available.
|
| X | ||||||||||
- Definition Amount of net assets (liabilities). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to intangibles acquired in connection with a business combination for which the initial accounting was incomplete. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount of property, plant, and equipment recognized as of the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Mountain Valley Pipeline (Details) - USD ($) $ in Millions |
1 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Jan. 31, 2016 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Schedule of Equity Method Investments [Line Items] | ||||
| Equity method investment | $ 467 | $ 488 | ||
| Mountain Valley Pipeline | Scenario, Forecast | Minimum | ||||
| Schedule of Equity Method Investments [Line Items] | ||||
| Payments to acquire equity interest | $ 3,000 | |||
| Mountain Valley Pipeline | Scenario, Forecast | Maximum | ||||
| Schedule of Equity Method Investments [Line Items] | ||||
| Payments to acquire equity interest | $ 3,500 | |||
| CET Gas | Mountain Valley Pipeline | ||||
| Schedule of Equity Method Investments [Line Items] | ||||
| Percentage of equity interest acquired | 12.50% | 12.50% | ||
| Payments to acquire equity interest | $ 18 | |||
| Equity method investment | $ 98 | $ 48 |
| X | ||||||||||
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - NY Transco (Details) - USD ($) $ in Millions |
1 Months Ended | ||
|---|---|---|---|
May 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Schedule of Equity Method Investments [Line Items] | |||
| Equity method investment | $ 467 | $ 488 | |
| CET Electric | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Ownership interest, percentage | 45.70% | ||
| CET Electric | NY Transco | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Ownership interest, percentage | 45.70% | ||
| Equity method investment | $ 53 | 51 | |
| CECONY | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Equity method investment | $ 0 | $ 0 | |
| CECONY | NY Transco | Equity Method Investee | Purchase Price of TOTS Project Transfer | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Amount of transaction | $ 122 | ||
| CECONY | NY Transco | Equity Method Investee | TOTS Project, Lease Payments | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Payment for easement rights | $ 8 |
| X | ||||||||||
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. No definition available.
|
| X | ||||||||||
- Definition Amount of transactions with related party during the financial reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Stagecoach Gas Services (Details) - USD ($) $ in Millions |
8 Months Ended | ||
|---|---|---|---|
Nov. 30, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Schedule of Equity Method Investments [Line Items] | |||
| Equity method investment | $ 467 | $ 488 | |
| CET Gas | Stagecoach Gas Services | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Payments to acquire equity interest | $ 974 | ||
| Percentage of equity interest acquired | 50.00% | ||
| Equity method investment | $ 971 | $ 992 |
| X | ||||||||||
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Pilesgrove (Details) $ in Millions |
1 Months Ended | |||
|---|---|---|---|---|
|
Aug. 31, 2016
USD ($)
|
Jun. 30, 2016
USD ($)
MW
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
|
|
| Pilesgrove | ||||
| Business Acquisition [Line Items] | ||||
| Generating capacity (MW AC) | MW | 18 | |||
| Net assets | $ 45 | $ 45 | ||
| Con Edison Development | Pilesgrove | ||||
| Business Acquisition [Line Items] | ||||
| Percentage of voting interest acquired | 50.00% | |||
| Purchase price | $ 16 | |||
| Bargain purchase gain | 8 | |||
| Bargain purchase gain, net of taxes | 5 | |||
| Non-utility property | 45 | |||
| Other current assets | $ 3 | |||
| Con Edison Development | Pilesgrove | ||||
| Business Acquisition [Line Items] | ||||
| Equity method investment, impairment charge | $ 8 | |||
| Equity method investment, impairment charge, net of taxes | $ 5 | |||
| Percentage of equity interest owned | 50.00% | |||
| X | ||||||||||
- Definition Business Combination, Bargain Purchase, Gain Recognized, Net of Tax No definition available.
|
| X | ||||||||||
- Definition Equity Method Investment, Other than Temporary Impairment, Net of Tax No definition available.
|
| X | ||||||||||
- Definition Generating Capacity No definition available.
|
| X | ||||||||||
- Definition Amount of net assets (liabilities). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition In a business combination in which the amount of net identifiable assets acquired and liabilities assumed exceeds the aggregate consideration transferred or to be transferred (as defined), this element represents the amount of gain recognized by the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount of property, plant, and equipment recognized as of the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Panoche Valley (Details) $ in Millions |
1 Months Ended | ||
|---|---|---|---|
|
Oct. 31, 2016
USD ($)
MW
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
|
|
| Panoche Valley | |||
| Business Acquisition [Line Items] | |||
| Generating capacity (MW AC) | MW | 240 | ||
| Net assets | $ 435 | $ 388 | |
| Con Edison Development | Panoche Valley | |||
| Business Acquisition [Line Items] | |||
| Percentage of voting interest acquired | 50.00% | ||
| Cash consideration | $ 28 | ||
| Outstanding note payable relieved at acquisition | 242 | ||
| Non-utility construction work in progress | 290 | ||
| Other assets | 22 | ||
| Current liabilities | $ 14 | ||
| Con Edison Development | Panoche Valley | |||
| Business Acquisition [Line Items] | |||
| Percentage of equity interest owned | 50.00% |
| X | ||||||||||
- Definition Business Combination, Long-term Debt Forgiven No definition available.
|
| X | ||||||||||
- Definition Generating Capacity No definition available.
|
| X | ||||||||||
- Definition Amount of net assets (liabilities). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount of property, plant, and equipment recognized as of the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Coram Wind (Details) - Coram Wind $ in Millions |
1 Months Ended | |
|---|---|---|
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
MW
|
|
| Business Acquisition [Line Items] | ||
| Generating capacity (MW AC) | MW | 102 | |
| Net assets | $ 87 | $ 96 |
| Con Edison Development | ||
| Business Acquisition [Line Items] | ||
| Percentage of voting interest acquired | 100.00% | |
| Purchase price | 97 | |
| Non-utility property | 191 | |
| Intangible assets | 78 | |
| Restricted cash, current | 8 | |
| Long-term debt | $ 180 | |
| Increase in intangible asset | $ 22 | |
| Decrease in non-utility property | $ 22 | |
| X | ||||||||||
- Definition Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Restricted Cash, Current No definition available.
|
| X | ||||||||||
- Definition Generating Capacity No definition available.
|
| X | ||||||||||
- Definition Amount of net assets (liabilities). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to property, plant, and equipment acquired in connection with a business combination for which the initial accounting was incomplete. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount of identifiable intangible assets recognized as of the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The amount of property, plant, and equipment recognized as of the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) to assets, excluding financial assets and goodwill, lacking physical substance with a finite life for purchase accounting adjustments. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Pike County Light & Power Company (Details) - Pike - USD ($) $ in Millions |
1 Months Ended | 12 Months Ended | |
|---|---|---|---|
Sep. 30, 2015 |
Aug. 31, 2016 |
Dec. 31, 2015 |
|
| Discontinued Operations, Held-for-sale | |||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | |||
| Impairment charge on assets held for sale | $ 5 | ||
| O&R | Discontinued Operations, Disposed of by Sale | |||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | |||
| Proceeds from divestiture of business | $ 15 | ||
| Period for transition services (up to) | 18 months | ||
| Agreement to purchase and sell, term | 3 years | ||
| Agreement to purchase and sell, term of extension option | 3 years | ||
| O&R | Discontinued Operations, Held-for-sale | |||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | |||
| Impairment charge on assets held for sale | $ 5 | ||
| Impairment of long-lived assets to be disposed of, net of tax | $ 3 |
| X | ||||||||||
- Definition Impairment of Long-Lived Assets to be Disposed of, Net of Tax No definition available.
|
| X | ||||||||||
- Definition Purchase and Sales Agreement, Extension Option, Term No definition available.
|
| X | ||||||||||
- Definition Purchase and Sales Agreement, Term No definition available.
|
| X | ||||||||||
- Definition Transition Services, Period No definition available.
|
| X | ||||||||||
- Definition The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
Acquisitions, Investments and Dispositions - Con Edison Solutions' Retail Electric Supply Business (Details) - Con Edison Solutions - Retail Electric Supply Business - Discontinued Operations, Disposed of by Sale $ in Millions |
1 Months Ended |
|---|---|
|
Sep. 30, 2016
USD ($)
| |
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | |
| Proceeds from divestiture of business | $ 235 |
| Gain on sale of business | 104 |
| Gain on sale of business, after tax | 56 |
| Gain on sale of derivatives | 65 |
| Gain on sale of derivatives, after tax | 42 |
| Tax effect of sale, state tax related to change in apportionment of state income taxes | 16 |
| Tax effect of sale, state tax related to change in apportionment of state income taxes, net of federal tax | $ 10 |
| X | ||||||||||
- Definition Gain (Loss) on Disposition of Business, Derivative No definition available.
|
| X | ||||||||||
- Definition Gain (Loss) on Disposition of Business, Derivative, Net of Tax No definition available.
|
| X | ||||||||||
- Definition Gain (Loss) on Disposition of Business, Net No definition available.
|
| X | ||||||||||
- Definition Gain (Loss) on Disposition of Business, State Tax Apportionment No definition available.
|
| X | ||||||||||
- Definition Gain (Loss) on Disposition of Business, State Tax Apportionment, Net of Federal Tax No definition available.
|
| X | ||||||||||
- Definition Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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| X | ||||||||||
- Details
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| X | ||||||||||
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Acquisitions, Investments and Dispositions - Upton 2 (Details) - Con Edison Development $ in Millions |
1 Months Ended | 12 Months Ended |
|---|---|---|
|
May 31, 2017
USD ($)
|
Dec. 31, 2018
MW
|
|
| Upton 2 | Scenario, Forecast | ||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | ||
| Generating capacity (MW AC) | MW | 180 | |
| Disposal Group, Disposed of by Sale, Not Discontinued Operations | Upton 2 | ||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | ||
| Consideration the project is sold | $ 11.0 | |
| Gain on sale of project | 1.0 | |
| Gain on sale of project, net of tax | $ 0.7 |
| X | ||||||||||
- Definition Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Net of Tax No definition available.
|
| X | ||||||||||
- Definition Generating Capacity No definition available.
|
| X | ||||||||||
- Definition Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation. No definition available.
|
| X | ||||||||||
- Definition Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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| X | ||||||||||
- Details
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Schedule I - Condensed Financial Information - Condensed Statement of Income and Comprehensive Income (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Condensed Income Statements,Captions [Line Items] | |||
| Interest expense | $ (729) | $ (696) | $ (653) |
| NET INCOME | 1,525 | 1,245 | 1,193 |
| Comprehensive Income | $ 1,526 | $ 1,252 | $ 1,204 |
| Net Income Per Share – Basic (dollars per share) | $ 4.97 | $ 4.15 | $ 4.07 |
| Net Income Per Share – Diluted (dollars per share) | 4.94 | 4.12 | 4.05 |
| Dividends Declared Per Share (dollars per share) | $ 2.76 | $ 2.68 | $ 2.60 |
| Average Number Of Shares Outstanding—Basic (In Millions) | 307.1 | 300.4 | 293.0 |
| Average Number Of Shares Outstanding—Diluted (In Millions) | 308.8 | 301.9 | 294.4 |
| Parent Company | |||
| Condensed Income Statements,Captions [Line Items] | |||
| Equity in earnings of subsidiaries | $ 1,544 | $ 1,254 | $ 1,195 |
| Other income (deductions), net of taxes | 31 | 32 | 27 |
| Interest expense | (50) | (41) | (29) |
| NET INCOME | 1,525 | 1,245 | 1,193 |
| Comprehensive Income | $ 1,526 | $ 1,252 | $ 1,204 |
| Average Number Of Shares Outstanding—Basic (In Millions) | 307.1 | 300.4 | 293.0 |
| Average Number Of Shares Outstanding—Diluted (In Millions) | 308.8 | 301.9 | 294.4 |
| X | ||||||||||
- Definition Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after tax of income (loss) of subsidiary attributable to the parent entity. No definition available.
|
| X | ||||||||||
- Definition Interest and debt related expenses associated with nonoperating financing activities of the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of income (expense) related to nonoperating activities, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Details
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Schedule I - Condensed Financial Information - Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Condensed Cash Flow Statements, Captions [Line Items] | |||
| Net Income | $ 1,525 | $ 1,245 | $ 1,193 |
| Change in Assets: | |||
| Taxes receivable | 15 | 87 | 58 |
| Other – net | (44) | 54 | (27) |
| NET CASH FLOWS FROM OPERATING ACTIVITIES | 3,367 | 3,459 | 3,277 |
| INVESTING ACTIVITIES | |||
| NET CASH FLOWS USED IN INVESTING ACTIVITIES | (3,703) | (4,976) | (3,657) |
| FINANCING ACTIVITIES | |||
| Net proceeds of short-term debt | (477) | (475) | 729 |
| Issuance of long-term debt | 1,697 | 2,590 | 1,147 |
| Retirement of long-term debt | (434) | (735) | (500) |
| Debt issuance costs | (19) | (24) | (15) |
| Issuance of common shares for stock plans, net of repurchases | 51 | 51 | 1 |
| Issuance of common shares - public offering | 343 | 702 | 0 |
| Common stock dividends | (803) | (763) | (733) |
| NET CASH FLOWS FROM FINANCING ACTIVITIES | 357 | 1,345 | 629 |
| NET CHANGE FOR THE PERIOD | 21 | (172) | 249 |
| BALANCE AT BEGINNING OF PERIOD | 776 | 944 | 699 |
| BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE | 797 | 776 | 944 |
| CECONY | |||
| Condensed Cash Flow Statements, Captions [Line Items] | |||
| Net Income | 1,104 | 1,056 | 1,084 |
| Change in Assets: | |||
| Other – net | 8 | (11) | 38 |
| NET CASH FLOWS FROM OPERATING ACTIVITIES | 2,866 | 3,038 | 2,819 |
| INVESTING ACTIVITIES | |||
| NET CASH FLOWS USED IN INVESTING ACTIVITIES | (3,078) | (2,739) | (2,638) |
| FINANCING ACTIVITIES | |||
| Net proceeds of short-term debt | (450) | (433) | 583 |
| Issuance of long-term debt | 1,200 | 1,300 | 650 |
| Retirement of long-term debt | 0 | (650) | (350) |
| Debt issuance costs | (15) | (13) | (7) |
| NET CASH FLOWS FROM FINANCING ACTIVITIES | 240 | (440) | 17 |
| NET CHANGE FOR THE PERIOD | 28 | (141) | 198 |
| BALANCE AT BEGINNING OF PERIOD | 702 | 843 | 645 |
| BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE | 730 | 702 | 843 |
| Parent Company | |||
| Condensed Cash Flow Statements, Captions [Line Items] | |||
| Net Income | 1,525 | 1,245 | 1,193 |
| Equity in earnings of subsidiaries | (1,544) | (1,254) | (1,195) |
| Change in Assets: | |||
| Special deposits | 0 | 0 | 0 |
| Taxes receivable | 34 | 87 | 58 |
| Other – net | 21 | (152) | (382) |
| NET CASH FLOWS FROM OPERATING ACTIVITIES | 896 | 723 | 635 |
| INVESTING ACTIVITIES | |||
| Contributions to subsidiaries | (434) | (691) | (15) |
| Long term debt receivable from affiliated companies | 0 | (900) | 0 |
| NET CASH FLOWS USED IN INVESTING ACTIVITIES | (434) | (1,591) | (15) |
| FINANCING ACTIVITIES | |||
| Net proceeds of short-term debt | (53) | (53) | 162 |
| Issuance of long-term debt | 400 | 900 | 0 |
| Retirement of long-term debt | (402) | (2) | (2) |
| Debt issuance costs | (2) | (5) | 0 |
| Issuance of common shares for stock plans, net of repurchases | 51 | 51 | 1 |
| Issuance of common shares - public offering | 343 | 702 | 0 |
| Common stock dividends | (803) | (763) | (733) |
| NET CASH FLOWS FROM FINANCING ACTIVITIES | (466) | 830 | (572) |
| NET CHANGE FOR THE PERIOD | (4) | (38) | 48 |
| BALANCE AT BEGINNING OF PERIOD | 13 | 51 | 3 |
| BALANCE AT END OF PERIOD EXCLUDING HELD FOR SALE | 9 | 13 | 51 |
| Parent Company | CECONY | |||
| Condensed Cash Flow Statements, Captions [Line Items] | |||
| Dividends received | 796 | 744 | 872 |
| Parent Company | O&R | |||
| Condensed Cash Flow Statements, Captions [Line Items] | |||
| Dividends received | 44 | 43 | 81 |
| Parent Company | Clean Energy Businesses | |||
| Condensed Cash Flow Statements, Captions [Line Items] | |||
| Dividends received | 12 | 10 | 8 |
| Parent Company | Con Edison Transmission | |||
| Condensed Cash Flow Statements, Captions [Line Items] | |||
| Dividends received | $ 8 | $ 0 | $ 0 |
| X | ||||||||||
- Definition Equity in earnings of subsidiaries No definition available.
|
| X | ||||||||||
- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition The net cash inflow or outflow for the increase (decrease) in the beginning and end of period deposits balances. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The increase (decrease) during the reporting period in income taxes receivable, which represents the amount due from tax authorities for refunds of overpayments or recoveries of income taxes paid. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of increase (decrease) in receivables classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow associated with extending a long-term loan to a related party. Alternate caption: Payments for Advances to Affiliates. No definition available.
|
| X | ||||||||||
- Definition Dividends received on equity and other investments during the current period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash inflow from the additional capital contribution to the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of cash inflow from issuance of shares under share-based compensation arrangement. Issuance includes, but is not limited to, exercise of stock options and similar instruments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net cash inflow or outflow for borrowing having initial term of repayment within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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Schedule I - Condensed Financial Information - Condensed Balance Sheet (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|---|
| Current Assets | ||||
| Cash and temporary cash investments | $ 797 | $ 776 | $ 944 | $ 699 |
| Taxes receivable | 64 | 79 | ||
| Prepayments | 178 | 159 | ||
| Other current assets | 189 | 151 | ||
| TOTAL CURRENT ASSETS | 3,537 | 3,406 | ||
| Investments in subsidiaries | 2,001 | 1,921 | ||
| Goodwill | 428 | 428 | ||
| Other noncurrent assets | 4,973 | 7,712 | ||
| TOTAL ASSETS | 48,111 | 48,255 | 45,642 | |
| Current Liabilities | ||||
| Long-term debt due within one year | 1,298 | 39 | ||
| Notes payable | 577 | 1,054 | ||
| Other current liabilities | 386 | 297 | ||
| TOTAL CURRENT LIABILITIES | 4,902 | 3,843 | ||
| Long-term debt | 14,731 | 14,735 | ||
| Shareholders’ Equity | ||||
| Equity | 15,418 | 14,298 | ||
| TOTAL LIABILITIES AND EQUITY | 48,111 | 48,255 | ||
| Parent Company | ||||
| Current Assets | ||||
| Cash and temporary cash investments | 9 | 13 | $ 51 | $ 3 |
| Taxes receivable | 45 | 79 | ||
| Accounts receivable from affiliated companies | 687 | 702 | ||
| Prepayments | 36 | 24 | ||
| Other current assets | 18 | 19 | ||
| TOTAL CURRENT ASSETS | 795 | 837 | ||
| Investments in subsidiaries | 15,110 | 13,991 | ||
| Goodwill | 406 | 406 | ||
| Deferred income tax | 18 | 42 | ||
| Long term debt receivable from affiliated companies | 900 | 900 | ||
| Other noncurrent assets | 2 | 16 | ||
| TOTAL ASSETS | 17,231 | 16,192 | ||
| Current Liabilities | ||||
| Long-term debt due within one year | 2 | 2 | ||
| Notes payable | 331 | 384 | ||
| Accounts payable to affiliated companies | 274 | 288 | ||
| Other current liabilities | 10 | 22 | ||
| TOTAL CURRENT LIABILITIES | 617 | 696 | ||
| Total Liabilities | 617 | 696 | ||
| Long-term debt | 1,195 | 1,198 | ||
| Shareholders’ Equity | ||||
| Common stock, including additional paid-in capital | 6,331 | 5,887 | ||
| Retained earnings | 9,088 | 8,411 | ||
| Equity | 15,419 | 14,298 | ||
| TOTAL LIABILITIES AND EQUITY | $ 17,231 | $ 16,192 |
| X | ||||||||||
- Definition Total value of common stock equity No definition available.
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| X | ||||||||||
- Definition Long-Term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership. This does not include advances to clients. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership, due within 1 year (or 1 business cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of payable due to an entity that is affiliated with the reporting entity by means of direct or indirect ownership. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Sum of the carrying values as of the balance sheet date of the portions of long-term notes payable due within one year or the operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of current assets classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of noncurrent assets classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of liabilities classified as other, due within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of asset related to consideration paid in advance for costs that provide economic benefits within a future period of one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The cumulative amount of the reporting entity's undistributed earnings or deficit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Details
|
Schedule II - Valuation and Qualifying Accounts (Details) - Allowance For Uncollectible Accounts - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | $ 83 | $ 96 | $ 106 |
| Charged To Costs And Expenses | 64 | 63 | 77 |
| Charged To Other Accounts | 0 | 0 | 0 |
| Deductions | 77 | 76 | 87 |
| Balance At End of Period | 70 | 83 | 96 |
| CECONY | |||
| Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | 78 | 91 | 98 |
| Charged To Costs And Expenses | 60 | 57 | 69 |
| Charged To Other Accounts | 0 | 0 | 0 |
| Deductions | 73 | 70 | 76 |
| Balance At End of Period | $ 65 | $ 78 | $ 91 |
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of increase in the allowances and reserves, which consist of the valuation and qualifying accounts that are either netted against the cost of an asset or that reflect a liability established to represent expected future costs, from charges to costs and expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of increase in the allowances and reserves, which consist of the valuation and qualifying accounts that are either netted against the cost of an asset or that reflect a liability established to represent expected future costs, from charges to accounts other than costs and expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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