Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details)	Dec. 31, 2021 MWh MW MMBTU gal
Electric Energy
Derivatives, Fair Value [Line Items]
Notional amount | MWh	26,982,370
Capacity
Derivatives, Fair Value [Line Items]
Notional amount | MW	42,333
Natural Gas
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	253,195,063
Refined Fuels
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,696,000
CECONY | Electric Energy
Derivatives, Fair Value [Line Items]
Notional amount | MWh	24,646,000
CECONY | Capacity
Derivatives, Fair Value [Line Items]
Notional amount | MW	28,800
CECONY | Natural Gas
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	235,570,000
CECONY | Refined Fuels
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,696,000