Current Expected Credit Losses - Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 616	$ 394	$ 620	$ 360
Recoveries	18	3	23	17
Write-offs	(120)	(29)	(218)	(95)
Reserve adjustments	101	66	190	152
Ending Balance	615	434	615	434
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	28	17	41	13
Recoveries	0	0	0	0
Write-offs	0	0	(4)	0
Reserve adjustments	14	8	5	12
Ending Balance	42	25	42	25
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	605	383	605	353
Recoveries	18	3	22	14
Write-offs	(118)	(28)	(213)	(90)
Reserve adjustments	100	61	191	142
Ending Balance	605	419	605	419
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	25	12	38	9
Recoveries	0	0	0	0
Write-offs	0	0	(4)	0
Reserve adjustments	10	9	1	12
Ending Balance	$ 35	$ 21	$ 35	$ 21