Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details)	Mar. 31, 2025 MMBTU gal MW MWh
Electric Energy (MWh)
Derivatives, Fair Value [Line Items]
Notional amount | MWh	29,654,925
Capacity (MW)
Derivatives, Fair Value [Line Items]
Notional amount | MW	26,400
Natural Gas (Dt)
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	289,040,000
Refined Fuels (gallons)
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,024,000
CECONY | Electric Energy (MWh) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MWh	27,053,975
CECONY | Capacity (MW) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MW	19,800
CECONY | Natural Gas (Dt) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	270,010,000
CECONY | Refined Fuels (gallons) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,024,000