Risk Management - Credit Risks (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Credit Derivatives [Line Items]
Additional collateral, aggregate fair value if downgraded	$ 0
Energy commodity derivative contracts
Credit Derivatives [Line Items]
Letter of credits outstanding	0	$ 0
Variation margin requirement	0	0
Contract and Over the Counter \| Energy commodity derivative contracts \| Statement of Financial Position Location Balance [Axis]: us-gaap:RestrictedCashAndInvestmentsCurrent
Credit Derivatives [Line Items]
Cash collateral posted	14	$ 24
Initial margin requirement	15
Variation margin requirement	$ 1

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

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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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Amount of deposit for derivative.

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Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Amount of receivable from positive price movement on derivative.

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