Regulatory Matters - Other Regulatory Matters Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024	May 31, 2024	Dec. 31, 2023
Public Utilities, General Disclosures [Line Items]
Other customer-provided capital rate (in percent)	475.00%	595.00%
Return on regulatory assets	$ 3,213	$ 3,262
Deferred derivative losses recovery period, current (in years)	1 year
Recovery period for deferred derivative losses (in years)	3 years
CECONY
Public Utilities, General Disclosures [Line Items]
Billing system costs	$ 510
Estimated capitalization costs	89
Incremental costs			$ 51
Net regulatory assets	1,061	1,078
CECONY | Maximum
Public Utilities, General Disclosures [Line Items]
Capital expenditures limit	$ 421		$ 421	$ 38
CECONY | Commodity
Public Utilities, General Disclosures [Line Items]
Recovery period (in years)	4 years
CECONY | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets	$ 2,991	3,024
O&R
Public Utilities, General Disclosures [Line Items]
Net regulatory assets	13	14
RECO | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets	$ 25	$ 28