Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details)	Jun. 30, 2025 MMBTU MWh gal MW
Electric Energy (MWh)
Derivatives, Fair Value [Line Items]
Notional amount | MWh	30,092,325
Capacity (MW)
Derivatives, Fair Value [Line Items]
Notional amount | MW	22,350
Natural Gas (Dt)
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	319,560,000
Refined Fuels (gallons)
Derivatives, Fair Value [Line Items]
Notional amount | gal	4,284,000
CECONY | Electric Energy (MWh) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MWh	27,209,175
CECONY | Capacity (MW) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MW	16,650
CECONY | Natural Gas (Dt) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	299,470,000
CECONY | Refined Fuels (gallons) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | gal	4,284,000