Current Expected Credit Losses - Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 620	$ 360
Recoveries	5	14
Write-offs	(98)	(66)
Reserve adjustments	89	86
Ending Balance	616	394
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	41	13
Recoveries	0	0
Write-offs	(4)	0
Reserve adjustments	(9)	4
Ending Balance	28	17
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	605	353
Recoveries	5	11
Write-offs	(96)	(62)
Reserve adjustments	91	81
Ending Balance	605	383
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	38	9
Recoveries	0	0
Write-offs	(4)	0
Reserve adjustments	(9)	3
Ending Balance	$ 25	$ 12