Current Expected Credit Losses - Rollforward of Segment Type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	$ 34	$ (78)
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	360	322
Recoveries	14	4
Write-offs	(66)	(48)
Reserve adjustments	86	(34)
Ending Balance	394	244
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	13	10
Recoveries	0	0
Write-offs	0	(1)
Reserve adjustments	4	1
Ending Balance	17	10
CECONY
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	30	(78)
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	353	314
Recoveries	11	4
Write-offs	(62)	(47)
Reserve adjustments	81	(35)
Ending Balance	383	236
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	9	7
Recoveries	0	0
Write-offs	0	0
Reserve adjustments	3	1
Ending Balance	$ 12	$ 8