Electricity and Gas Purchase Agreements - Summary of Capacity, Energy and Other Fixed Payments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	$ 596	$ 552	$ 486
Astoria Generating Company
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	45	20	26
Brooklyn Navy Yard
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	165	139	113
Gas transportation and storage
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	386	393	347
CECONY
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	550	506	446
CECONY | Astoria Generating Company
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	45	20	26
CECONY | Brooklyn Navy Yard
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	165	139	113
CECONY | Gas transportation and storage
Long-term Contract for Purchase of Electric Power [Line Items]
Capacity, energy and other fixed payments	$ 340	$ 347	$ 307