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Investments (Tables) | 3 Months Ended
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Mar. 31, 2015
Schedule of Investments [Line Items] |
Unconsolidated Equity Investments | Equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three months ended March 31 was as follows (in millions):
| Alliant Energy |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014
ATC |  | ($7.8 | ) |  |  | ($11.2 | ) |  |  | ($7.8 | ) |  |  | ($11.2 | )
Other | 1.3 |  |  | (0.2 | ) |  | — |  |  | (0.2 | )
|  | ($6.5 | ) |  |  | ($11.4 | ) |  |  | ($7.8 | ) |  |  | ($11.4 | )
WPL [Member] |
Schedule of Investments [Line Items] |
Unconsolidated Equity Investments | Equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three months ended March 31 was as follows (in millions):
| Alliant Energy |  | WPL
| 2015 |  | 2014 |  | 2015 |  | 2014
ATC |  | ($7.8 | ) |  |  | ($11.2 | ) |  |  | ($7.8 | ) |  |  | ($11.2 | )
Other | 1.3 |  |  | (0.2 | ) |  | — |  |  | (0.2 | )
|  | ($6.5 | ) |  |  | ($11.4 | ) |  |  | ($7.8 | ) |  |  | ($11.4 | )

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- Definition Tabular disclosure of equity method investments including, but not limited to, name of each investee or group of investments, percentage ownership, difference between recorded amount of an investment and the value of the underlying equity in the net assets, and summarized financial information. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 + Details
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