Related Party Transactions - Summary of Costs of Administrative and Other Services Provided and Received (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Related Party Transaction [Line Items]
Cost of services provided	$ 4,530	$ 4,092	$ 12,924	$ 11,587
Cost of services received	3,562	3,230	10,476	9,364
CECONY
Related Party Transaction [Line Items]
Cost of services provided	4,181	3,762	11,963	10,730
Cost of services received	3,267	2,959	9,635	8,623
CECONY | Related Party
Related Party Transaction [Line Items]
Cost of services provided	41	39	118	106
Cost of services received	$ 21	$ 21	$ 64	$ 62