Regulatory Matters - Other Regulatory Matters (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Apr. 30, 2023
Public Utilities, General Disclosures [Line Items]
Other customer-provided capital rate (in percent)	5.20%	1.75%
Return on regulatory assets	$ 2,406.0		$ 2,304.0
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]
Estimated capitalization costs				$ 75.0
Billing system costs	$ 452.9
Net regulatory assets	$ 1,116.0		1,150.0
CECONY | Maximum
Public Utilities, General Disclosures [Line Items]
Capital expenditures limit				$ 421.0
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	$ 2,233.0		2,097.0
O&R
Public Utilities, General Disclosures [Line Items]
Net regulatory assets	19.0		22.0
RECO | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets	$ 19.0		$ 21.0