New Financial Accounting Standards	12 Months Ended
Dec. 31, 2018
Accounting Changes and Error Corrections [Abstract]
New Financial Accounting Standards	New Financial Accounting Standards In January 2019, the Companies adopted Accounting Standards Update (ASU) No. 2016-02, “Leases (Topic 842),” including the amendments thereto (the New Standard), using a modified retrospective transition method of adoption. The New Standard supersedes the lease requirements within Accounting Standard Codification (ASC) Topic 840, “Leases.” The New Standard requires lessees to recognize assets and liabilities on the balance sheet and disclose key information about leasing arrangements. Under the New Standard, 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). The Utilities, as regulated entities, are permitted to continue to recognize expense using the timing that conforms to the regulatory rate treatment. Lessor accounting is similar to the previous model, but updated to align with “Revenue from Contracts with Customers (Topic 606)." Upon adoption of the New Standard, the Companies elected the following practical expedients: (1) for leases commenced prior to adoption date, the following three transition expedients that will allow the Companies to not reassess: (a) whether expired contracts contain leases; (b) the lease classification for expired leases and (c) the initial direct costs for existing leases; (2) for an underlying asset class, an expedient that allows the Companies to not apply the recognition requirements to short-term leases and an expedient that will allow the Companies to account for lease and associated non-lease components as a single lease component; (3) an expedient that allows the use of hindsight to determine lease term; and (4) an expedient that allows the Companies 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 Topic 840. For leases previously classified as operating leases, upon adoption of the New Standard, the Companies recognized on their balance sheets right-of-use assets and corresponding lease liabilities of approximately $875 million and $635 million for Con Edison and CECONY, respectively, as of January 1, 2019. The adoption of the New Standard will not have a material effect on the Companies’ liquidity or results of operations. The Companies will prepare additional disclosures as required by the New Standard beginning in 2019. The Companies implemented additional internal controls related to the New Standard, however the adoption of the New Standard is not expected to require a change that will materially affect the Companies’ internal control over financial reporting. 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 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 will not 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, and the Companies plan to adopt the amendments, for reporting periods beginning after December 15, 2018. The application of the guidance will not have a material impact 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, with early adoption permitted. The Companies adopted the amendments in the fourth quarter of 2018. The impact of adoption on the Companies’ financial position, results of operations and liquidity was immaterial. In August 2018, the FASB issued amendments to the guidance for internal use software through ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract.” The amendments align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019, with early adoption permitted. The Companies elected to adopt the amendments in the third quarter of 2018, prospectively for all in-scope implementation costs incurred after the date of adoption. The impact of adoption on the Companies’ financial position, results of operations and liquidity was immaterial.

New Financial Accounting Standards

In January 2019, the Companies adopted Accounting Standards Update (ASU) No. 2016-02, “Leases (Topic 842),” including the amendments thereto (the New Standard), using a modified retrospective transition method of adoption. The New Standard supersedes the lease requirements within Accounting Standard Codification (ASC) Topic 840, “Leases.” The New Standard requires lessees to recognize assets and liabilities on the balance sheet and disclose key information about leasing arrangements. Under the New Standard, 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). The Utilities, as regulated entities, are permitted to continue to recognize expense using the timing that conforms to the regulatory rate treatment. Lessor accounting is similar to the previous model, but updated to align with “Revenue from Contracts with Customers (Topic 606)."

Upon adoption of the New Standard, the Companies elected the following practical expedients: (1) for leases commenced prior to adoption date, the following three transition expedients that will allow the Companies to not reassess: (a) whether expired contracts contain leases; (b) the lease classification for expired leases and (c) the initial direct costs for existing leases; (2) for an underlying asset class, an expedient that allows the Companies to not apply the recognition requirements to short-term leases and an expedient that will allow the Companies to account for lease and associated non-lease components as a single lease component; (3) an expedient that allows the use of hindsight to determine lease term; and (4) an expedient that allows the Companies 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 Topic 840. For leases previously classified as operating leases, upon adoption of the New Standard, the Companies recognized on their balance sheets right-of-use assets and corresponding lease liabilities of approximately $875 million and $635 million for Con Edison and CECONY, respectively, as of January 1, 2019.

The adoption of the New Standard will not have a material effect on the Companies’ liquidity or results of operations. The Companies will prepare additional disclosures as required by the New Standard beginning in 2019. The Companies implemented additional internal controls related to the New Standard, however the adoption of the New Standard is not expected to require a change that will materially affect the Companies’ internal control over financial reporting.

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 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 will not 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, and the Companies plan to adopt the amendments, for reporting periods beginning after December 15, 2018. The application of the guidance will not have a material impact 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, with early adoption permitted. The Companies adopted the amendments in the fourth quarter of 2018. The impact of adoption on the Companies’ financial position, results of operations and liquidity was immaterial.

In August 2018, the FASB issued amendments to the guidance for internal use software through ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract.” The amendments align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. For public entities, the amendments are effective for reporting periods beginning after December 15, 2019, with early adoption permitted. The Companies elected to adopt the amendments in the third quarter of 2018, prospectively for all in-scope implementation costs incurred after the date of adoption. The impact of adoption on the Companies’ financial position, results of operations and liquidity was immaterial.