Current Expected Credit Losses - Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments			$ (12)	$ 165
Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments			(7)	162
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 336	$ 275	317	148
Recoveries	4	3	13	9
Write-offs	2	(24)	(62)	(66)
Reserve adjustments	(37)	59	37	222
Ending Balance	305	313	305	313
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	9	7	22	7
Recoveries	0	0	0	0
Write-offs	(2)	0	(5)	(1)
Reserve adjustments	2	0	(8)	1
Ending Balance	9	7	9	7
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	324	262	304	138
Recoveries	4	3	12	8
Write-offs	4	(23)	(56)	(62)
Reserve adjustments	(35)	58	37	216
Ending Balance	297	300	297	300
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	7	4	19	4
Recoveries	0	0	0	0
Write-offs	(1)	0	(3)	0
Reserve adjustments	1	1	(9)	1
Ending Balance	$ 7	$ 5	$ 7	$ 5