Capitalization - Schedule of Carrying Amounts and Fair Values of Long-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Debt Instrument [Line Items]
Long-term debt (including current portion)	$ 25,554	$ 25,551
Unamortized debt expense	246	249
Carrying Amount
Debt Instrument [Line Items]
Long-term debt (including current portion)	25,804	25,801
Fair Value
Debt Instrument [Line Items]
Long-term debt (including current portion)	23,244	23,633
CECONY
Debt Instrument [Line Items]
Long-term debt (including current portion)	24,063	24,060
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	237	240
CECONY | Carrying Amount
Debt Instrument [Line Items]
Long-term debt (including current portion)	24,313	24,310
CECONY | Fair Value
Debt Instrument [Line Items]
Long-term debt (including current portion)	$ 21,920	$ 22,291