Current Expected Credit Losses - Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments			$ (47)	$ 19
Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments			(48)	20
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 244	$ 336	322	317
Recoveries	4	5	8	10
Write-offs	(44)	(34)	(91)	(63)
Reserve adjustments	71	29	36	72
Ending Balance	275	336	275	336
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	10	25	10	22
Recoveries	0	0	0	0
Write-offs	0	0	(1)	(4)
Reserve adjustments	18	(16)	19	(9)
Ending Balance	28	9	28	9
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	236	324	314	304
Recoveries	3	5	7	9
Write-offs	(41)	(32)	(89)	(60)
Reserve adjustments	68	27	34	71
Ending Balance	266	324	266	324
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	8	23	7	19
Recoveries	0	0	0	0
Write-offs	0	0	0	(3)
Reserve adjustments	16	(16)	17	(9)
Ending Balance	$ 24	$ 7	$ 24	$ 7