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Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 1,136 | $ 1,130
Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 563 | 566
Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 380 | 366
Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 49 | 65
Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 61 | 48
Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 83 | 85
IPL [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 648 | 644
IPL [Member] | Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 297 | 299
IPL [Member] | Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 241 | 242
IPL [Member] | Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 28 | 34
IPL [Member] | Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 25 | 13
IPL [Member] | Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 57 | 56
WPL [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 488 | 486
WPL [Member] | Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 266 | 267
WPL [Member] | Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 139 | 124
WPL [Member] | Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 21 | 31
WPL [Member] | Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 36 | 35
WPL [Member] | Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 26 | $ 29

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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//1943274/2147481854/980-405-25-1 + Details
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Balance Type: | credit
Period Type: | instant

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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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