Income Tax - Additional Information (Details) - USD ($)		3 Months Ended		6 Months Ended
	Mar. 01, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)		$ 29,000,000	$ 17,000,000	$ 272,000,000	$ 171,000,000
Gain on sale of the Clean Energy Businesses		$ 13,000,000	$ 0	$ 867,000,000	$ 0
Gain on sale of subsidiary	$ 867,000,000
Gain on sale of subsidiary, after tax	$ 804,000,000
State income tax, net of federal income tax benefit (in percent)		2.00%	7.00%	4.00%	6.00%
Estimated liability for uncertain tax positions		$ 26,000,000		$ 26,000,000
Research and development credits				3,000,000
Effective income tax rate reconciliation, uncertainty of taxes				23,000,000
Total amount of unrecognized tax benefits, if recognized, that would reduce effective tax rate		26,000,000		26,000,000
Penalties recognized for uncertain tax positions				0	$ 0
State and Local Jurisdiction | New York State Division of Taxation and Finance
Income Taxes Disclosure [Line Items]
Expected minimum loss				$ 5,000,000
State income tax, net of federal income tax benefit (in percent)				7.25%
State and Local Jurisdiction | Metropolitan Transportation Authority Subcharge
Income Taxes Disclosure [Line Items]
State income tax, net of federal income tax benefit (in percent)				9.425%
Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)		34,000,000	$ (10,000,000)	$ 189,000,000	108,000,000
CECONY | Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)		$ (34,000,000)	$ (10,000,000)	$ 189,000,000	$ 108,000,000
State income tax, net of federal income tax benefit (in percent)		5.00%	5.00%	5.00%	5.00%
Increase in accumulated deferred tax liabilities		$ 10,000,000
Estimated liability for uncertain tax positions		9,000,000		$ 9,000,000
Effective income tax rate reconciliation, uncertainty of taxes				6,000,000
Total amount of unrecognized tax benefits, if recognized, that would reduce effective tax rate		9,000,000		9,000,000
Clean Energy Businesses
Income Taxes Disclosure [Line Items]
Gain on sale of the Clean Energy Businesses				202,000,000
Deferred tax asset, remeasurement of state taxes		10,000,000		10,000,000
Deferred tax benefit, valuation allowance		10,000,000		10,000,000
Deferred tax assets, tax credits		$ 107,000,000		107,000,000
Deferred state taxes benefit				$ 44,000,000