Derivative Instruments and Hedging Activities - Schedule of Notional Amounts of Outstanding (Details) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2026 USD ($) MWh BTU	Dec. 31, 2025 USD ($) BTU MWh
Long \| Interest
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount \| $	$ 3,971	$ 4,080
Heat Rate Call Option Commodity Contracts \| Short \| Power
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount, energy measure \| MWh	23	29
Heat Rate Call Option Commodity Contracts \| Short \| Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount, energy measure \| BTU	2	5

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details