Current Expected Credit Losses - Schedule of Major Portfolio Segment Type (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	$ 360	$ 322	$ 317
Recoveries	21	14	17
Write-offs	(250)	(138)	(103)
Reserve adjustments	489	162	91
Ending Balance December 31,	620	360	322
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	13	10	22
Recoveries	0	0	0
Write-offs	0	(5)	(6)
Reserve adjustments	28	8	(6)
Ending Balance December 31,	41	13	10
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	353	314	304
Recoveries	17	12	16
Write-offs	(239)	(131)	(94)
Reserve adjustments	474	158	88
Ending Balance December 31,	605	353	314
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	9	7	19
Recoveries	0	0	0
Write-offs	0	(3)	(4)
Reserve adjustments	29	5	(8)
Ending Balance December 31,	$ 38	$ 9	$ 7