Income Tax - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025	Dec. 31, 2024
Income Taxes Disclosure [Line Items]
Income Tax Expense	$ 303.0	$ 242.0
Accrued income taxes	53.0		$ 154.0	$ 154.0
Increase (decrease) in corporate alternative minimum tax (CAMT) carry forward	205.0
Estimated liability for uncertain tax positions	10.0
Unrecognized tax benefits, increase resulting from current period tax positions	0.4
Unrecognized tax benefits, net	9.0
Subsidiaries | CECONY
Income Taxes Disclosure [Line Items]
Income Tax Expense	231.0	$ 227.0
Accrued income taxes	45.0
Increase (decrease) in corporate alternative minimum tax (CAMT) carry forward	213.0
Estimated liability for uncertain tax positions	5.0
Unrecognized tax benefits, increase resulting from current period tax positions	$ 0.4