Income Tax - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Income Taxes Disclosure [Line Items]
Income tax expense	$ 242,000,000	$ 184,000,000
Accrued income taxes	0		$ 0
Estimated liability for uncertain tax positions	10,000,000
Unrecognized tax benefits, increase resulting from current period tax positions	1,000,000
Unrecognized tax benefits, net	9,000,000
Unrecognized tax benefits, interest expenses	0	0
Unrecognized tax benefits penalties	0	0
CECONY
Income Taxes Disclosure [Line Items]
Income tax expense	227,000,000	181,000,000
Subsidiaries | CECONY
Income Taxes Disclosure [Line Items]
Income tax expense	227,000,000	$ 181,000,000
Estimated liability for uncertain tax positions	$ 6,000,000