XML 61 R41.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Common Stock and Earnings Per Share (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2015
Common Stock and Earnings Per Share [Abstract] |
Summary of Common Stock [Table Text Block] |
Summary of Common Stock | Shares |  | Equity |
| Thousands |  | Millions |
Balance as of December 31, 2012 | 39,377 |  |  | $784.7 |
Employee Stock Purchase Program | 16 |  | 0.7 |
Invest Direct | 395 |  | 18.5 |
Options and Stock Awards | 301 |  | 17.9 |
Equity Issuance Program | 1,312 |  | 63.4 |
Balance as of December 31, 2013 | 41,401 |  | 885.2 |
Employee Stock Purchase Program | 18 |  | 0.8 |
Invest Direct | 378 |  | 18.9 |
Options and Stock Awards | 78 |  | 8.0 |
Equity Issuance Program | 1,851 |  | 90.0 |
Forward Sale Agreement and Issuance | 1,807 |  | 85.2 |
Contribution to Pension | 396 |  | 19.5 |
Balance as of December 31, 2014 | 45,929 |  | 1,107.6 |
Employee Stock Purchase Program | 18 |  | 0.9 |
Invest Direct | 383 |  | 19.0 |
Options and Stock Awards | 43 |  | 8.6 |
Equity Issuance Program | 1,289 |  | 69.9 |
Forward Sale Agreement | 1,413 |  | 65.4 |
Balance as of December 31, 2015 | 49,075 |  |  | $1,271.4 |
Reconciliation of Basic and Diluted Earnings Per Share [Table Text Block] |
Reconciliation of Basic and Diluted |  |  |
Earnings Per Share |  |  | Dilutive |  |  |
Year Ended December 31 | Basic |  | Securities |  | Diluted |
Millions Except Per Share Amounts |  |  |
2015 |  |  |
Net Income Attributable to ALLETE |  | $141.1 |  |  |  |  | $141.1 |
Average Common Shares | 48.3 |  | 0.1 |  | 48.4 |
Earnings Per Share |  | $2.92 |  |  |  |  | $2.92 |
2014 |  |  |
Net Income Attributable to ALLETE |  | $124.8 |  |  |  |  | $124.8 |
Average Common Shares | 42.9 |  | 0.2 |  | 43.1 |
Earnings Per Share |  | $2.91 |  |  |  |  | $2.90 |
2013 |  |  |
Net Income Attributable to ALLETE |  | $104.7 |  |  |  |  | $104.7 |
Average Common Shares | 39.7 |  | 0.1 |  | 39.8 |
Earnings Per Share |  | $2.64 |  |  |  |  | $2.63 |

X
- Definition Common Stock and Earnings Per Share [Abstract] + References No definition available. + Details
Name: | ale_CommonStockAndEarningsPerShareAbstract
Namespace Prefix: | ale_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the change in common stock outstanding. + References No definition available. + Details
Name: | us-gaap_ScheduleOfCommonStockOutstandingRollForwardTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of an entity's basic and diluted earnings per share calculations, including a reconciliation of numerators and denominators of the basic and diluted per-share computations for income from continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
Name: | us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration