Current Expected Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase in allowance for uncollectible accounts resulting from COVID-19 pandemic	$ 169	$ 78
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	169	78	$ 8
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	148	70
Recoveries	14	8
Write-offs	(91)	(54)
Reserve adjustments	246	124
Ending Balance December 31,	317	148	70
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	7	4
Recoveries	1	0
Write-offs	(2)	(2)
Reserve adjustments	16	5
Ending Balance December 31,	22	7	4
CECONY
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase in allowance for uncollectible accounts resulting from COVID-19 pandemic	166	73
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments	166	74	7
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	138	65
Recoveries	12	6
Write-offs	(86)	(50)
Reserve adjustments	240	117
Ending Balance December 31,	304	138	65
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at January 1,	4	3
Recoveries	1	0
Write-offs	(1)	(1)
Reserve adjustments	15	2
Ending Balance December 31,	$ 19	$ 4	$ 3