Derivatives - Schedule of Notional Amounts of Outstanding Derivative Positions (Details) gal in Millions, certificate in Millions, T in Millions, MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) certificate GWh MMBTU T gal	Dec. 31, 2023 USD ($) certificate MMBTU GWh T gal
Natural gas
Derivatives, Fair Value [Line Items]
Derivative, nonmonetary notional amount, energy measure | MMBTU	4,568	5,335
Electricity
Derivatives, Fair Value [Line Items]
Derivative, nonmonetary notional amount, energy measure | GWh	796,982	800,001
Financial transmission rights / Congestion revenue rights
Derivatives, Fair Value [Line Items]
Derivative, nonmonetary notional amount, energy measure | GWh	248,742	250,895
Coal
Derivatives, Fair Value [Line Items]
Derivative, nonmonetary notional amount, mass | T	27	35
Fuel oil
Derivatives, Fair Value [Line Items]
Derivative, nonmonetary notional amount, volume | gal	2	3
Emissions
Derivatives, Fair Value [Line Items]
Derivative, nonmonetary notional amount, mass | T	28	24
Renewable energy certificates
Derivatives, Fair Value [Line Items]
Nonmonetary notional volume | certificate	31	29
Interest rate swaps – variable/fixed
Derivatives, Fair Value [Line Items]
Derivative, notional amount | $	$ 5,300	$ 5,225
Interest rate swaps - fixed/variable
Derivatives, Fair Value [Line Items]
Derivative, notional amount | $	$ 700	$ 1,300