Derivative Instruments and Hedging Activities - Hedged Volume of Derivative Transactions (Details)	Sep. 30, 2024 MW MWh gal MMBTU
Electric Energy (MWh)
Derivatives, Fair Value [Line Items]
Notional amount | MWh	36,052,760
Capacity (MW)
Derivatives, Fair Value [Line Items]
Notional amount | MW	36,600
Natural Gas (Dt)
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	337,880,000
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	32,953,250
CECONY | Capacity (MW) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MW	28,200
CECONY | Natural Gas (Dt) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | MMBTU	316,190,000
CECONY | Refined Fuels (gallons) | Subsidiaries
Derivatives, Fair Value [Line Items]
Notional amount | gal	2,520,000