Related Party Transactions - Additional Information (Details) MMBTU in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) MMBTU	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Related Party Transaction [Line Items]
Net assets	$ 21,078,000,000		$ 21,078,000,000		$ 20,687,000,000
Other income	210,000,000	$ 101,000,000	625,000,000	$ 296,000,000
CECONY
Related Party Transaction [Line Items]
Net assets	19,113,000,000	16,867,000,000	19,113,000,000	16,867,000,000	16,878,000,000	$ 18,843,000,000	$ 18,892,000,000	$ 16,568,000,000	$ 16,618,000,000	$ 16,312,000,000
Income taxes due to Con Edison			418,000,000		(89,000,000)
Funding limit of CECONY to O&R (not to exceed)			250,000,000
CECONY | Subsidiaries
Related Party Transaction [Line Items]
Sale of natural gas	14,000,000	26,000,000	$ 60,000,000	97,000,000
CECONY | Related Party, Lending of Funds
Related Party Transaction [Line Items]
Lending period (not more than) (months)			12 months
CECONY | Equity Method Investee | Mountain Valley Pipeline LLC
Related Party Transaction [Line Items]
Contract term (years)			20 years
Generating capacity per day (in dekatherms) | MMBTU			250
CECONY | Related Party | Financial Electric Capacity Contract | Con Edison Energy
Related Party Transaction [Line Items]
Gain (loss) on financial electric capacity contracts		1,000,000		2,000,000
O&R
Related Party Transaction [Line Items]
Net assets	1,057,000,000		$ 1,057,000,000
Outstanding loans	0		0		$ 0
CET Electric | NY Transco | Related Party
Related Party Transaction [Line Items]
Other income	$ 1,000,000	$ 2,000,000	$ 7,000,000	$ 6,000,000
CET Electric | New York Transco's New York Enery Solution Project
Related Party Transaction [Line Items]
Ownership interest (in percent)	45.70%		45.70%
CET Electric | New York Transco's Propel NY Energy Project
Related Party Transaction [Line Items]
Ownership interest (in percent)	41.70%		41.70%