Fair Value Measurements, Including Derivatives (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis and Included in Level 3) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Regulatory Assets
Beginning balance	$ 270	$ 253	$ 370	$ 176
Included in earnings:
Purchased power	2	(1)	5	(3)
Fuel used in electric generation	(1)	0	(1)	0
Settlements	(11)	(1)	(25)	1
Purchases	0	0	0	7
Ending balance	265	283	265	283
Other Regulatory Assets Liabilities
Included in earnings:
Included in regulatory assets/liabilities	$ 5	$ 32	$ (84)	$ 102

Gain loss on fuel used in electric generation.

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- Definition

Gain (Loss) on purchased power.

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Gain loss on purchases.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
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- Definition

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

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- Definition

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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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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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