v2.4.0.6
Investments
 9 Months Ended
Sep. 30, 2012
Schedule of Equity Method Investments [Line Items]  
Investments
INVESTMENTS
Unconsolidated Equity Investments - Equity (income) loss from Alliant Energy’s and WPL’s unconsolidated investments accounted for under the equity method of accounting for the three and nine months ended September 30 was as follows (in millions):
 
Alliant Energy
 
WPL
 
Three Months
 
Nine Months
 
Three Months
 
Nine Months
 
2012
 
2011
 
2012
 
2011
 
2012
 
2011
 
2012
 
2011
American Transmission Company LLC (ATC)

($10.4
)
 

($9.7
)
 

($30.6
)
 

($28.2
)
 

($10.4
)
 

($9.7
)
 

($30.6
)
 

($28.2
)
Other
—

 
(0.4
)
 
0.2

 
(1.4
)
 
(0.1
)
 
(0.1
)
 
(0.6
)
 
(0.7
)
 

($10.4
)
 

($10.1
)
 

($30.4
)
 

($29.6
)
 

($10.5
)
 

($9.8
)
 

($31.2
)
 

($28.9
)


Summary financial information from the unaudited financial statements of ATC for the three and nine months ended September 30 was as follows (in millions):
 
Three Months
 
Nine Months
 
2012
 
2011
 
2012
 
2011
Operating revenues
$150.3
 
$142.8
 
$450.1
 
$420.6
Operating income
81.5
 
76.4
 
240.0
 
228.1
Net income
60.5
 
56.6
 
177.9
 
166.5
WPL [Member]
  
Schedule of Equity Method Investments [Line Items]  
Investments
INVESTMENTS
Unconsolidated Equity Investments - Equity (income) loss from Alliant Energy’s and WPL’s unconsolidated investments accounted for under the equity method of accounting for the three and nine months ended September 30 was as follows (in millions):
 
Alliant Energy
 
WPL
 
Three Months
 
Nine Months
 
Three Months
 
Nine Months
 
2012
 
2011
 
2012
 
2011
 
2012
 
2011
 
2012
 
2011
American Transmission Company LLC (ATC)

($10.4
)
 

($9.7
)
 

($30.6
)
 

($28.2
)
 

($10.4
)
 

($9.7
)
 

($30.6
)
 

($28.2
)
Other
—

 
(0.4
)
 
0.2

 
(1.4
)
 
(0.1
)
 
(0.1
)
 
(0.6
)
 
(0.7
)
 

($10.4
)
 

($10.1
)
 

($30.4
)
 

($29.6
)
 

($10.5
)
 

($9.8
)
 

($31.2
)
 

($28.9
)


Summary financial information from the unaudited financial statements of ATC for the three and nine months ended September 30 was as follows (in millions):
 
Three Months
 
Nine Months
 
2012
 
2011
 
2012
 
2011
Operating revenues
$150.3
 
$142.8
 
$450.1
 
$420.6
Operating income
81.5
 
76.4
 
240.0
 
228.1
Net income
60.5
 
56.6
 
177.9
 
166.5