Capitalization - Carrying Amounts and Fair Values of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Unamortized debt expense	$ 222	$ 202
Carrying Amount
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	22,177	20,796
Fair Value
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	20,525	18,234
CECONY
Debt Instrument [Line Items]
Unamortized debt discount	215	195
CECONY | Carrying Amount
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	21,060	19,080
CECONY | Fair Value
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	19,517	16,699
Clean Energy Businesses | Carrying Amount
Debt Instrument [Line Items]
Long-Term Debt (including current portion)		2,645
Clean Energy Businesses | Fair Value
Debt Instrument [Line Items]
Long-Term Debt (including current portion)		$ 2,489
Broken Bow II | Carrying Amount
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	62
Broken Bow II | Fair Value
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	$ 58