Current Expected Credit Losses - Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 434	$ 275	$ 360	$ 322
Recoveries	0	3	17	11
Write-offs	(65)	(43)	(160)	(135)
Reserve adjustments	92	41	244	78
Ending Balance	461	276	461	276
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	25	28	13	10
Recoveries	0	0	0	0
Write-offs	0	(4)	0	(5)
Reserve adjustments	(1)	7	11	26
Ending Balance	24	31	24	31
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	419	266	353	314
Recoveries	0	3	13	10
Write-offs	(63)	(41)	(152)	(130)
Reserve adjustments	92	41	234	75
Ending Balance	448	269	448	269
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	21	24	9	7
Recoveries	0	0	0	0
Write-offs	0	(3)	0	(3)
Reserve adjustments	0	6	12	23
Ending Balance	$ 21	$ 27	$ 21	$ 27