Related Party Transactions - Schedule of Costs of Administrative and Other Services Provided and Received (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Related Party Transaction [Line Items]
Cost of services provided	$ 5,095	$ 4,798
Cost of services received	3,918	3,673
CECONY
Related Party Transaction [Line Items]
Cost of services provided	4,654	4,441
Cost of services received	3,548	3,374
CECONY | Related Party
Related Party Transaction [Line Items]
Cost of services provided	39	40
Cost of services received	$ 21	$ 21