Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details)	Mar. 31, 2022 MW gal MWh MMBTU
Electric Energy (MWh)
Derivatives, Fair Value [Line Items]
Notional amount | MWh	24,078,605
Capacity (MW)
Derivatives, Fair Value [Line Items]
Notional amount | MW	37,114
Natural Gas (Dt)
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	229,787,936
Refined Fuels (gallons)
Derivatives, Fair Value [Line Items]
Notional amount | gal	2,688,000
CECONY | Electric Energy (MWh) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MWh	22,015,475
CECONY | Capacity (MW) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MW	26,100
CECONY | Natural Gas (Dt) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	214,090,000
CECONY | Refined Fuels (gallons) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | gal	2,688,000