Related Party Transactions - Additional Information (Details) MMBTU in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) MMBTU	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Net assets	$ 20,037,000,000	$ 18,847,000,000
CECONY
Related Party Transaction [Line Items]
Net assets	16,312,000,000	14,849,000,000	$ 14,147,000,000	$ 12,910,000,000
Sale of natural gas	90,000,000	59,000,000	71,000,000
Funding limit of CECONY to O&R (not to exceed)	$ 250,000,000
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
Related Party Transaction [Line Items]
Amount of transaction	$ 0	0
Contract term (years)	20 years
Generating capacity per day (in dekatherms) | MMBTU	250
CECONY | Equity Method Investee | Stagecoach | Purchased Power Costs
Related Party Transaction [Line Items]
Amount of transaction	$ 31,000,000	34,000,000	$ 33,000,000
CECONY | Affiliated Entity | Financial Electric Capacity Contract | Con Edison Energy
Related Party Transaction [Line Items]
Loss on financial electric capacity contracts	(4,000,000)
O&R
Related Party Transaction [Line Items]
Net assets	888,000,000
Outstanding loans	$ 0	$ 0
CET Electric | NY Transco
Related Party Transaction [Line Items]
Ownership interest, percentage	45.70%
Amounts billed	$ 5,900,000
CET Gas | Mountain Valley Pipeline
Related Party Transaction [Line Items]
Percentage of equity interest owned	10.20%	11.30%
Expected reduction in equity interest	8.50%