Summary of Significant Accounting Policies and Other Matters - Other Deferred Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Public Utility, Property, Plant and Equipment [Line Items]
Prepayments	$ 24	$ 16
Other deferred charges and noncurrent assets	105	81
Depreciation expense, other deferred charges and noncurrent assets and prepayments	15	12
Accumulated depreciation, other deferred charges and noncurrent assets and prepayments	37	22
CECONY
Public Utility, Property, Plant and Equipment [Line Items]
Prepayments	23	15
Other deferred charges and noncurrent assets	103	78
Depreciation expense, other deferred charges and noncurrent assets and prepayments	14	11
Accumulated depreciation, other deferred charges and noncurrent assets and prepayments	$ 33	$ 19