Schedule II - Valuation and Qualifying Accounts (Details) - Allowance For Uncollectible Accounts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 154	$ 74	$ 68
Charged To Costs And Expenses	83	72	77
Charged To Other Accounts	0	0	0
Deductions	102	8	(71)
Balance At End of Period	339	154	74
CECONY
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	143	68	61
Charged To Costs And Expenses	78	65	72
Charged To Other Accounts	0	0	0
Deductions	102	10	(65)
Balance At End of Period	$ 323	$ 143	$ 68