Fair Value Measurements, Including Derivatives (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis and Included in Level 3) (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($)
Regulatory Assets
Beginning balance	$ 0
Included in earnings:
Purchased power	8
Settlements	(8)
Ending balance	148
Other Regulatory Assets Liabilities
Included in earnings:
Included in regulatory assets/liabilities	$ 148

Costs of power used for operations in prior periods that were expected to be recovered from customers in future periods.

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Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of gain (loss) included in earnings for investments classified as other.

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Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

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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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