XML 57 R8.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Investments | 3 Months Ended
--- | ---
Mar. 31, 2014
Schedule of Equity Method Investments [Line Items] |
Investments | INVESTMENTS 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
| 2014 |  | 2013 |  | 2014 |  | 2013
ATC |  | ($11.2 | ) |  |  | ($10.3 | ) |  |  | ($11.2 | ) |  |  | ($10.3 | )
Other | (0.2 | ) |  | (0.4 | ) |  | (0.2 | ) |  | (0.5 | )
|  | ($11.4 | ) |  |  | ($10.7 | ) |  |  | ($11.4 | ) |  |  | ($10.8 | )
WPL’s Noncontrolling Interest - As of December 31, 2013, WPL, through its ownership interest in WPL Transco, held a 16% ownership interest in ATC. In January 2014, WPL Transco’s operating agreement was amended to allow ATI, a wholly-owned subsidiary of Resources, to become a member of WPL Transco in addition to WPL. ATI is expected to fund future capital contributions that WPL Transco will make to ATC. The first such contribution by ATI was in the first quarter of 2014. As of March 31, 2014, WPL’s noncontrolling interest reflects ATI’s ownership interest in WPL Transco, which was presented in total equity on WPL’s balance sheet. As a result of ATI funding future capital contributions to ATC, WPL’s ownership interest in WPL Transco is expected to decrease over time and ATI’s ownership interest in WPL Transco is expected to increase over time. WPL Transco’s equity income from ATC and future ATC dividends received by WPL Transco will be allocated between WPL and ATI based on their respective ownership interests at the time the equity income is generated and at the time of the dividend payments. Alliant Energy’s aggregate investment in ATC is not expected to change as a result of WPL Transco’s amended operating agreement.
WPL [Member] |
Schedule of Equity Method Investments [Line Items] |
Investments | INVESTMENTS 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
| 2014 |  | 2013 |  | 2014 |  | 2013
ATC |  | ($11.2 | ) |  |  | ($10.3 | ) |  |  | ($11.2 | ) |  |  | ($10.3 | )
Other | (0.2 | ) |  | (0.4 | ) |  | (0.2 | ) |  | (0.5 | )
|  | ($11.4 | ) |  |  | ($10.7 | ) |  |  | ($11.4 | ) |  |  | ($10.8 | )
WPL’s Noncontrolling Interest - As of December 31, 2013, WPL, through its ownership interest in WPL Transco, held a 16% ownership interest in ATC. In January 2014, WPL Transco’s operating agreement was amended to allow ATI, a wholly-owned subsidiary of Resources, to become a member of WPL Transco in addition to WPL. ATI is expected to fund future capital contributions that WPL Transco will make to ATC. The first such contribution by ATI was in the first quarter of 2014. As of March 31, 2014, WPL’s noncontrolling interest reflects ATI’s ownership interest in WPL Transco, which was presented in total equity on WPL’s balance sheet. As a result of ATI funding future capital contributions to ATC, WPL’s ownership interest in WPL Transco is expected to decrease over time and ATI’s ownership interest in WPL Transco is expected to increase over time. WPL Transco’s equity income from ATC and future ATC dividends received by WPL Transco will be allocated between WPL and ATI based on their respective ownership interests at the time the equity income is generated and at the time of the dividend payments. Alliant Energy’s aggregate investment in ATC is not expected to change as a result of WPL Transco’s amended operating agreement.

X
- Definition Description containing equity method investments, cash surrender value of life insurance policies and other investments disclosure as a single block of text. + References No definition available. + Details
Name: | lnt_InvestmentsTextBlock
Namespace Prefix: | lnt_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration