Current Expected Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase in allowance for uncollectible accounts resulting from COVID-19 pandemic	$ 0	$ 94	$ 19	$ 127
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments			19	127
Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Reserve adjustments			20	124
Accounts receivable - customers
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at April 1,	336	181	317	148
Recoveries	5	3	10	6
Write-offs	(34)	(21)	(63)	(41)
Reserve adjustments	29	112	72	162
Ending Balance June 30,	336	275	336	275
Other receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at April 1,	25	7	22	7
Recoveries	0	0	0	0
Write-offs	0	0	(4)	(1)
Reserve adjustments	(16)	0	(9)	1
Ending Balance June 30,	9	7	9	7
CECONY | Subsidiaries
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase in allowance for uncollectible accounts resulting from COVID-19 pandemic	(1)	91	20	124
CECONY | Accounts receivable - customers | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at April 1,	324	171	304	138
Recoveries	5	2	9	5
Write-offs	(32)	(19)	(60)	(39)
Reserve adjustments	27	108	71	158
Ending Balance June 30,	324	262	324	262
CECONY | Other receivables | Subsidiaries
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance at April 1,	23	5	19	4
Recoveries	0	0	0	0
Write-offs	0	0	(3)	0
Reserve adjustments	(16)	(1)	(9)	0
Ending Balance June 30,	$ 7	$ 4	$ 7	$ 4