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Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 1,028.0 | $ 1,130.0
Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 582.0 | 566.0
Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 347.0 | 366.0
Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 53.0 | 65.0
Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 17.0 | 48.0
Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 29.0 | 85.0
IPL [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 546.0 | 644.0
IPL [Member] | Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 286.0 | 299.0
IPL [Member] | Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 205.0 | 242.0
IPL [Member] | Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 29.0 | 34.0
IPL [Member] | Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 12.0 | 13.0
IPL [Member] | Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 14.0 | 56.0
WPL [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 482.0 | 486.0
WPL [Member] | Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 296.0 | 267.0
WPL [Member] | Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 142.0 | 124.0
WPL [Member] | Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 24.0 | 31.0
WPL [Member] | Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 5.0 | 35.0
WPL [Member] | Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 15.0 | $ 29.0

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- 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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