Capitalization - Carrying Amounts and Fair Values of Long-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Long-term debt (including current portion)	$ 24,653	$ 24,651
Unamortized debt expense	247	249
Carrying Amount
Debt Instrument [Line Items]
Long-term debt (including current portion)	24,653	24,651
Fair Value
Debt Instrument [Line Items]
Long-term debt (including current portion)	22,224	21,997
CECONY
Debt Instrument [Line Items]
Long-term debt (including current portion)	23,411	23,409
CECONY | Subsidiaries
Debt Instrument [Line Items]
Unamortized debt discount	239	241
CECONY | Carrying Amount | Subsidiaries
Debt Instrument [Line Items]
Long-term debt (including current portion)		23,409
CECONY | Fair Value | Subsidiaries
Debt Instrument [Line Items]
Long-term debt (including current portion)	$ 21,123	20,915
Broken Bow II | Carrying Amount
Debt Instrument [Line Items]
Long-term debt (including current portion)		$ 59