Capitalization - Carrying Amounts and Fair Values of Long-Term Debt (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Unamortized debt expense	$ 200	$ 202
Carrying Amount
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	21,300	20,796
Fair Value
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	17,726	18,234
CECONY | Subsidiaries
Debt Instrument [Line Items]
Unamortized debt discount	192	195
CECONY | Carrying Amount | Subsidiaries
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	19,583	19,080
CECONY | Fair Value | Subsidiaries
Debt Instrument [Line Items]
Long-Term Debt (including current portion)	$ 16,213	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