XML 70 R37.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Common Equity (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2018
Schedule of Common Equity [Line Items] |
Common Stock Activity | A summary of Alliant Energy’s common stock activity was as follows:
| 2018 |  | 2017 |  | 2016
Shares outstanding, January 1 | 231,348,646 |  |  | 227,673,654 |  |  | 226,918,432 |
At-the-market offering programs | 4,171,013 |  |  | 3,074,931 |  |  | — |
Shareowner Direct Plan issuances | 576,965 |  |  | 640,723 |  |  | 732,814 |
Equity-based compensation plans (Note 13(b)) | 5,078 |  |  | 5,185 |  |  | 22,408 |
Other | (38,423 | ) |  | (45,847 | ) |  | — |
Shares outstanding, December 31 | 236,063,279 |  |  | 231,348,646 |  |  | 227,673,654 |

X
- Definition [Line Items] for Schedule of Common Equity [Table] + References No definition available. + Details
Name: | lnt_ScheduleOfCommonEquityLineItems
Namespace Prefix: | lnt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_ScheduleOfCapitalUnitsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration