Summary of Significant Accounting Policies and Other Matters (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Reclassification	Reclassification Certain prior period amounts have been reclassified to conform with the 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 exercise 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, that 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, that 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 2024, the SEC issued a final rule, The Enhancement and Standardization of Climate-Related Disclosures for Investors, that requires registrants to provide climate-related disclosures in annual reports. The rule was subjected to litigation upon its release, and multiple challenges to the rule are currently pending with the United States Court of Appeals for the Eight Circuit. As a result, the SEC has temporarily stayed its rule pending judicial review. The results of the legal challenges and potential SEC actions may materially alter the terms of the rule as described below. Beginning with the 2025 annual report, the Companies would be required to provide additional disclosures in the Management Discussion and Analysis (MD&A) section of the SEC Form 10-K, and in the footnotes to the financial statements. The MD&A disclosures would describe material climate-related risks and their impacts, as well as board oversight of such risks. The footnote disclosures would quantify the impacts of severe weather events and other natural conditions, if material, and provide additional qualitative disclosures. Finally, the rule creates a new section of annual reports related to Scope 1 and Scope 2 greenhouse gas emission disclosures, beginning with the 2026 annual report. If any of the greenhouse gases specified in the rule is individually material, that would need to be separately disclosed. Qualitative disclosures related to the methodology, significant inputs and assumptions used to calculate GHG emissions are also required. The greenhouse gas emission disclosures would be subject to limited and then reasonable assurance for years beginning in 2029 and 2033, respectively. The Companies are evaluating the requirements of the final rule, and closely monitoring legal developments. The Companies do not expect the final rule to have a material impact on results of operations, financial position, or liquidity. However, there are substantial disclosure requirements and the Companies have cross-functional working groups assessing the implications and implementing best practices.