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Related Parties (Service Agreements) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2022 | Mar. 31, 2021
Corporate Services Billings [Member] | IPL [Member] |  |
Related Party Transactions [Line Items] |  |
Amounts billed between related parties | $ 40 | $ 40
Corporate Services Billings [Member] | WPL [Member] |  |
Related Party Transactions [Line Items] |  |
Amounts billed between related parties | 36 | 35
Sales Credited [Member] | IPL [Member] |  |
Related Party Transactions [Line Items] |  |
Amounts billed between related parties | 0 | 1
Sales Credited [Member] | WPL [Member] |  |
Related Party Transactions [Line Items] |  |
Amounts billed between related parties | 18 | 1
Purchases Billed [Member] | IPL [Member] |  |
Related Party Transactions [Line Items] |  |
Amounts billed between related parties | 94 | 143
Purchases Billed [Member] | WPL [Member] |  |
Related Party Transactions [Line Items] |  |
Amounts billed between related parties | $ 22 | $ 26

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- Definition Amount of transactions with related party during the financial reporting period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864 + 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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- Details
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- Details
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- Details
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- Details
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Data Type: | na
Balance Type: |
Period Type: |

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- Details
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- Details
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- Details
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