Related Party Transactions - Additional Information (Details) MMBTU in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) MMBTU	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Related Party Transaction [Line Items]
Net assets		$ 21,560,000,000		$ 21,560,000,000		$ 21,158,000,000
Other income		155,000,000	$ 210,000,000	319,000,000	$ 414,000,000
Unconditional charitable contribution, accrued amount	$ 12,000,000
CECONY
Related Party Transaction [Line Items]
Net assets		19,570,000,000	18,843,000,000	19,570,000,000	18,843,000,000	19,146,000,000	$ 19,597,000,000	$ 18,892,000,000	$ 16,878,000,000
Income taxes due to Con Edison				57,000,000		110,000,000
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	13,000,000	$ 38,000,000	46,000,000
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				200
O&R
Related Party Transaction [Line Items]
Net assets		1,084,000,000		$ 1,084,000,000
Outstanding loans		0		0		$ 0
CET Electric | NY Transco | Related Party
Related Party Transaction [Line Items]
Other income		$ (2,000,000)	$ 2,000,000	$ (1,000,000)	$ 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%
CET Electric | Mountain Valley Pipeline LLC
Related Party Transaction [Line Items]
Ownership interest (in percent)		6.70%		6.70%