Current Expected Credit Losses - Schedule of Major Portfolio Segment Type (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	$ 38	$ 5	$ 169
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	322	317	148
Recoveries	14	17	14
Write-offs	(138)	(103)	(91)
Reserve adjustments	162	91	246
Ending Balance December 31,	360	322	317
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	10	22	7
Recoveries	0	0	1
Write-offs	(5)	(6)	(2)
Reserve adjustments	8	(6)	16
Ending Balance December 31,	13	10	22
CECONY
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	39	10	166
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	314	304	138
Recoveries	12	16	12
Write-offs	(131)	(94)	(86)
Reserve adjustments	158	88	240
Ending Balance December 31,	353	314	304
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	7	19	4
Recoveries	0	0	1
Write-offs	(3)	(4)	(1)
Reserve adjustments	5	(8)	15
Ending Balance December 31,	$ 9	$ 7	$ 19