Related Party Transactions - Additional Information (Details) MMBTU in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) MMBTU	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Related Party Transaction [Line Items]
Net assets		$ 21,615,000,000		$ 21,158,000,000
Other income		164,000,000	$ 204,000,000
Subsequent Event
Related Party Transaction [Line Items]
Unconditional charitable contribution, accrued amount	$ 12,000,000
CECONY
Related Party Transaction [Line Items]
Net assets		19,597,000,000	18,892,000,000	19,146,000,000	$ 16,878,000,000
Income taxes due to Con Edison		110,000,000		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		$ 24,000,000	33,000,000
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
O&R
Related Party Transaction [Line Items]
Net assets		$ 1,098,000,000
Outstanding loans		0		$ 0
CET Electric | NY Transco | Related Party
Related Party Transaction [Line Items]
Other income		$ 1,000,000	$ 4,000,000
CET Electric | New York Transco's New York Enery Solution Project
Related Party Transaction [Line Items]
Ownership interest (in percent)		45.70%
CET Electric | New York Transco's Propel NY Energy Project
Related Party Transaction [Line Items]
Ownership interest (in percent)		41.70%