Income Tax - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	$ 184	$ 243
Estimated liability for uncertain tax positions	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
CECONY
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	181
CECONY | Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	181	$ 154
Estimated liability for uncertain tax positions	7
Unrecognized tax benefits, increase resulting from current period tax positions	$ 1