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Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 1,134	$ 1,028
Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	658	582
Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	351	347
Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	49	53
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	76	46
IPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	558	546
IPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	301	286
IPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	206	205
IPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	25	29
IPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	26	26
WPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	576	482
WPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	357	296
WPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	145	142
WPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	24	24
WPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 50	$ 20

X

- Definition

The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 405
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477571/980-405-25-1

+ Details

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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.

+ Details

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