Income Tax - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	$ (10)	$ 29	$ 174	$ 272
Estimated liability for uncertain tax positions	12		12
Unrecognized tax benefits, increase resulting from current period tax positions			1
Effective income tax rate reconciliation, uncertainty of taxes			3
Unrecognized tax benefits, net	11		11
CECONY
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	1	34	182	189
CECONY | Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	1	$ 34	182	$ 189
Estimated liability for uncertain tax positions	$ 8		8
Unrecognized tax benefits, increase resulting from current period tax positions			$ 1