Regulatory Matters - Other Regulatory Matters Narrative (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023	May 31, 2024	May 31, 2023
Public Utilities, General Disclosures [Line Items]
Other customer-provided capital rate (in percent)	5.95%	5.20%
Return on regulatory assets	$ 2,950	$ 2,541
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	1,082	1,113
CECONY | Maximum
Public Utilities, General Disclosures [Line Items]
Capital expenditures limit	$ 421	38		$ 421
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	$ 2,758	2,359
O&R
Public Utilities, General Disclosures [Line Items]
Net regulatory assets	16	18
RECO | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets	$ 24	$ 24