Derivative Instruments and Hedging Activities - Schedule of Hedged Volume of Derivative Transactions (Details)	Dec. 31, 2025 MW gal MWh MMBTU
Electric Energy
Derivatives, Fair Value [Line Items]
Notional amount | MWh	36,356,085
Capacity
Derivatives, Fair Value [Line Items]
Notional amount | MW	29,550
Natural Gas
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	311,800,000
Refined Fuels
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,780,000
CECONY | Electric Energy
Derivatives, Fair Value [Line Items]
Notional amount | MWh	34,025,975
CECONY | Capacity
Derivatives, Fair Value [Line Items]
Notional amount | MW	19,350
CECONY | Natural Gas
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	292,490,000
CECONY | Refined Fuels
Derivatives, Fair Value [Line Items]
Notional amount | gal	3,780,000