Related Party Transactions - Summary of Costs of Administrative and Other Services Provided and Received (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Related Party Transaction [Line Items]
Cost of services provided	$ 4,798	$ 4,280
Cost of services received	3,673	3,239
CECONY
Related Party Transaction [Line Items]
Cost of services provided	4,441	3,971
Cost of services received	3,374	2,982
CECONY | Related Party
Related Party Transaction [Line Items]
Cost of services provided	40	32
Cost of services received	$ 21	$ 20