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Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions | Jun. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 1,208 | $ 1,324
Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 572 | 579
Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 405 | 398
Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 90 | 210
Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 39 | 40
Electric transmission cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 19 | 20
WPL's West Riverside liquidated damages [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 17 | 32
Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 66 | 45
IPL [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 676 | 754
IPL [Member] | Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 301 | 303
IPL [Member] | Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 260 | 259
IPL [Member] | Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 48 | 115
IPL [Member] | Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 15 | 38
IPL [Member] | Electric transmission cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 14 | 10
IPL [Member] | Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 38 | 29
WPL [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 532 | 570
WPL [Member] | Tax-related [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 271 | 276
WPL [Member] | Cost of removal obligations [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 145 | 139
WPL [Member] | Derivatives [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 42 | 95
WPL [Member] | Commodity cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 24 | 2
WPL [Member] | Electric transmission cost recovery [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 5 | 10
WPL [Member] | WPL's West Riverside liquidated damages [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | 17 | 32
WPL [Member] | Other [Member] |  |
Regulatory Liabilities [Line Items] |  |
Regulatory liabilities | $ 28 | $ 16

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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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