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Regulatory Matters (Assets Retired Early) (Details) - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021
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Regulatory Assets [Line Items] |  |
Regulatory assets | $ 2,046 | $ 1,940
Assets retired early [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 70 | 92
IPL [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 1,386 | 1,443
IPL [Member] | Assets retired early [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 53 | 66
IPL [Member] | Assets retired early [Member] | Sutherland Units 1 and 3 [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 16 |
IPL [Member] | Assets retired early [Member] | M.L. Kapp Unit 2 [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 13 |
IPL [Member] | Assets retired early [Member] | Analog Electric Meters [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 24 |
WPL [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 660 | 497
WPL [Member] | Assets retired early [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | 17 | $ 26
WPL [Member] | Assets retired early [Member] | Edgewater Unit 4 [Member] |  |
Regulatory Assets [Line Items] |  |
Regulatory assets | $ 17 |

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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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- 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 -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
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