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Investments (Tables) | 6 Months Ended
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Jun. 30, 2021
Schedule of Equity Method Investments [Line Items] |
Unconsolidated Equity Investments | Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and six months ended June 30 was as follows (in millions):
| Three Months |  | Six Months
| 2021 |  | 2020 |  | 2021 |  | 2020
ATC Holdings | ($11) |  | ($14) |  | ($22) |  | ($25)
Other | (8) |  | (4) |  | (12) |  | (6)
| ($19) |  | ($18) |  | ($34) |  | ($31)

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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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