Summary of Significant Accounting Policies and Other Matters (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Reclassification	Reclassification Certain prior period amounts have been reclassified within the Companies' Consolidated Statements of Cash Flows and Consolidated Balance Sheets to conform with current period presentation.
Earnings Per Common Share	Earnings Per Common Share Con Edison presents basic and diluted earnings per share (EPS) on the face of its consolidated income statement. Basic EPS is calculated by dividing earnings available to common shareholders (“Net income for common stock” 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 estimated vesting price.
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: •Level 1 – Consists of assets or liabilities whose value is based on unadjusted quoted prices in active markets at the measurement date. An active market is one in which transactions for assets or liabilities occur with sufficient frequency and volume to provide pricing information on an ongoing basis. This category includes contracts traded on active exchange markets valued using unadjusted prices quoted directly from the exchange. •Level 2 – Consists of assets or liabilities valued using industry standard models and based on prices, other than quoted prices within Level 1, that are either directly or indirectly observable as of the measurement date. The industry standard models consider observable assumptions including time value, volatility factors and current market and contractual prices for the underlying commodities, in addition to other economic measures. This category includes contracts traded on active exchanges or in over-the-counter markets priced with industry standard models. •Level 3 – Consists of assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost benefit constraints. This category includes contracts priced using models that are internally developed and contracts placed in illiquid markets. It also includes contracts that expire after the period of time for which quoted prices are available and internal models are used to determine a significant portion of the value.
New Financial Accounting Standards	New Financial Accounting Standards In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (ASU 2020-04). In 2017, the United Kingdom’s Financial Conduct Authority announced that it intends to stop persuading or compelling banks to submit the London Interbank Offered Rate (LIBOR), a benchmark interest rate referenced in a variety of agreements, after 2021. The United Kingdom's Financial Conduct Authority ceased publication of U.S. Dollar LIBOR after December 31, 2021 for one-week and two-month U.S. Dollar LIBOR tenors, and expects to cease publishing after June 30, 2023 for all other U.S. Dollar LIBOR tenors. ASU 2020-04 provides entities with optional expedients and exceptions for applying generally accepted accounting principles to contract modifications and hedging relationships, subject to meeting certain criteria, that reference LIBOR or another reference rate expected to be discontinued. In January 2021, the FASB issued amendments to the guidance through ASU 2021-01 to include all contract modifications and hedging relationships affected by reference rate reform, including those that do not directly reference LIBOR or another reference rate expected to be discontinued, and clarify which optional expedients may be applied to them. As the Companies continue to modify contracts that contain references to LIBOR to allow for the use of an alternative rate, they have applied the practical expedient to not assess each change for a contract modification. The guidance can be applied prospectively. The optional relief is temporary and generally cannot be applied to contract modifications and hedging relationships entered into or evaluated after December 31, 2022. The Companies do not expect the new guidance to have a material impact on their financial position, results of operations or liquidity. In December 2021, the FASB issued amendments to the guidance on accounting for government assistance through ASU 2021-10, Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance. The amendments require that business entities disclose 1) the types of assistance, 2) an entity’s accounting for the assistance, and 3) the effect of the assistance on an entity’s financial statements. For public entities, the amendments are effective for reporting periods beginning after December 15, 2021. Early adoption is permitted. The Companies have concluded the new guidance will not have a material impact on the Companies’ financial position, results of operations and liquidity.