Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details)	Sep. 30, 2023 MW MMBTU MWh gal
Electric Energy (MWh)
Derivatives, Fair Value [Line Items]
Notional amount | MWh	30,376,045
Capacity (MW)
Derivatives, Fair Value [Line Items]
Notional amount | MW	49,800
Natural Gas (Dt)
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	353,360,000
Refined Fuels (gallons)
Derivatives, Fair Value [Line Items]
Notional amount | gal	2,520,000
CECONY | Electric Energy (MWh) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MWh	27,714,325
CECONY | Capacity (MW) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MW	39,000
CECONY | Natural Gas (Dt) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	334,950,000
CECONY | Refined Fuels (gallons) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | gal	2,520,000