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Regulatory Matters - Schedule of Composition of Regulatory Assets (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	$ 1,132	$ 1,150
Current regulatory assets	22	19
Total regulatory assets	1,154	1,169
Removal costs recoverable through rates
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	323	356
Deferred pension expense
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	276	318
Customer lead line replacements
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	80	86
Unamortized debt expense
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	84	84
Regulatory balancing accounts
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	65	71
Programmed maintenance expense
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	60	57
Purchase premium recoverable through rates
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	49	50
Other
Regulatory Assets [Line Items]
Total (non-current) regulatory assets	$ 195	$ 128

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- Definition

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.

+ References

No definition available.

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- Definition

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478742/980-340-50-1

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Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost.

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-Section 50
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Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

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