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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Related Party Transaction [Line Items]
Cost of services provided	$ 4,092	$ 3,872	$ 11,587	$ 11,219
Cost of services received	3,230	3,149	9,364	9,340
CECONY
Related Party Transaction [Line Items]
Cost of services provided	3,762	3,590	10,730	10,287
Cost of services received	2,959	2,911	8,623	8,537
CECONY | Related Party
Related Party Transaction [Line Items]
Cost of services provided	39	39	106	105
Cost of services received	$ 21	$ 21	$ 62	$ 61