Current Expected Credit Losses - Schedule of Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 507	$ 620
Recoveries	20	5
Write-offs	(111)	(98)
Reserve adjustments	52	89
Ending Balance	468	616
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	35	41
Recoveries	0	0
Write-offs	0	(4)
Reserve adjustments	(25)	(9)
Ending Balance	10	28
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	500	605
Recoveries	19	5
Write-offs	(109)	(96)
Reserve adjustments	50	91
Ending Balance	460	605
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	27	38
Recoveries	0	0
Write-offs	0	(4)
Reserve adjustments	(19)	(9)
Ending Balance	$ 8	$ 25