Capitalization - Carrying Amounts and Fair Values of Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Long-term debt (including current portion)	$ 24,657	$ 24,651
Unamortized debt expense	243	249
Carrying Amount
Debt Instrument [Line Items]
Long-term debt (including current portion)	24,657	24,651
Fair Value
Debt Instrument [Line Items]
Long-term debt (including current portion)	22,316	21,997
CECONY
Debt Instrument [Line Items]
Long-term debt (including current portion)	23,415	23,409
CECONY | Subsidiaries
Debt Instrument [Line Items]
Unamortized debt discount	235	241
CECONY | Carrying Amount | Subsidiaries
Debt Instrument [Line Items]
Long-term debt (including current portion)	23,415	23,409
CECONY | Fair Value | Subsidiaries
Debt Instrument [Line Items]
Long-term debt (including current portion)	$ 21,216	20,915
Broken Bow II | Carrying Amount
Debt Instrument [Line Items]
Long-term debt (including current portion)		$ 59