Current Expected Credit Losses - Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	$ (78)	$ 19
Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	(78)	20
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	322	317
Recoveries	4	5
Write-offs	(48)	(30)
Reserve adjustments	(34)	44
Ending Balance	244	336
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	10	22
Recoveries	0	0
Write-offs	(1)	(3)
Reserve adjustments	1	6
Ending Balance	10	25
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	314	304
Recoveries	4	4
Write-offs	(47)	(28)
Reserve adjustments	(35)	44
Ending Balance	236	324
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	7	19
Recoveries	0	0
Write-offs	0	(2)
Reserve adjustments	1	6
Ending Balance	$ 8	$ 23