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Common Equity (Tables) | 12 Months Ended
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Dec. 31, 2016
Schedule of Common Equity [Line Items] |
Common Stock Activity | A summary of Alliant Energy’s common stock activity was as follows:
| 2016 |  | 2015 |  | 2014
Shares outstanding, January 1 | 226,918,432 |  |  | 221,871,360 |  |  | 221,887,338 |
At-the-market offering program | — |  |  | 4,373,234 |  |  | — |
Shareowner Direct Plan issuances | 732,814 |  |  | 606,010 |  |  | — |
Equity-based compensation plans (Note 12(b)) | 22,408 |  |  | 112,756 |  |  | 71,094 |
Other | — |  |  | (44,928 | ) |  | (87,072 | )
Shares outstanding, December 31 | 227,673,654 |  |  | 226,918,432 |  |  | 221,871,360 |

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- Definition Tabular disclosure of an entity's capital units or capital shares, including the value of capital units or capital shares, units authorized, units outstanding and other information necessary to a fair presentation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04.16) -URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996 + Details
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