XML 50 R27.htm IDEA: XBRL DOCUMENT v3.7.0.1
Income Taxes (Tables)
 3 Months Ended
Mar. 31, 2017
Income Taxes [Line Items]  
Schedule Of Effective Income Tax Rates
The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.
 
Alliant Energy
 
IPL
 
WPL
Three Months Ended March 31
2017
 
2016
 
2017
 
2016
 
2017
 
2016
Statutory federal income tax rate
35.0
 %
 
35.0
 %
 
35.0
%
 
35.0
%
 
35.0
 %
 
35.0
 %
IPL’s tax benefit riders
(7.8
)
 
(8.7
)
 
(19.4
)
 
(20.7
)
 
—

 
—

Effect of rate-making on property-related differences
(7.5
)
 
(6.8
)
 
(17.9
)
 
(15.2
)
 
(1.7
)
 
(0.8
)
Production tax credits
(5.9
)
 
(6.3
)
 
(6.6
)
 
(6.7
)
 
(7.0
)
 
(6.5
)
Other items, net
1.0

 
4.5

 
(1.3
)
 
5.9

 
4.7

 
4.8

Overall income tax rate
14.8
%
 
17.7
%
 
(10.2
%)
 
(1.7
%)
 
31.0
%
 
32.5
%
Summary Of Tax Credit Carryforwards
At March 31, 2017, carryforwards and expiration dates were estimated as follows (in millions):
 
Range of Expiration Dates
 
Alliant Energy
 
IPL
 
WPL
Federal net operating losses
2030-2037
 

$633

 

$315

 

$217

State net operating losses
2018-2037
 
696

 
13

 
2

Federal tax credits
2022-2037
 
284

 
104

 
118
IPL [Member]  
Income Taxes [Line Items]  
Schedule Of Effective Income Tax Rates
The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.
 
Alliant Energy
 
IPL
 
WPL
Three Months Ended March 31
2017
 
2016
 
2017
 
2016
 
2017
 
2016
Statutory federal income tax rate
35.0
 %
 
35.0
 %
 
35.0
%
 
35.0
%
 
35.0
 %
 
35.0
 %
IPL’s tax benefit riders
(7.8
)
 
(8.7
)
 
(19.4
)
 
(20.7
)
 
—

 
—

Effect of rate-making on property-related differences
(7.5
)
 
(6.8
)
 
(17.9
)
 
(15.2
)
 
(1.7
)
 
(0.8
)
Production tax credits
(5.9
)
 
(6.3
)
 
(6.6
)
 
(6.7
)
 
(7.0
)
 
(6.5
)
Other items, net
1.0

 
4.5

 
(1.3
)
 
5.9

 
4.7

 
4.8

Overall income tax rate
14.8
%
 
17.7
%
 
(10.2
%)
 
(1.7
%)
 
31.0
%
 
32.5
%
Summary Of Tax Credit Carryforwards
At March 31, 2017, carryforwards and expiration dates were estimated as follows (in millions):
 
Range of Expiration Dates
 
Alliant Energy
 
IPL
 
WPL
Federal net operating losses
2030-2037
 

$633

 

$315

 

$217

State net operating losses
2018-2037
 
696

 
13

 
2

Federal tax credits
2022-2037
 
284

 
104

 
118
WPL [Member]  
Income Taxes [Line Items]  
Schedule Of Effective Income Tax Rates
The overall income tax rates shown in the following table were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.
 
Alliant Energy
 
IPL
 
WPL
Three Months Ended March 31
2017
 
2016
 
2017
 
2016
 
2017
 
2016
Statutory federal income tax rate
35.0
 %
 
35.0
 %
 
35.0
%
 
35.0
%
 
35.0
 %
 
35.0
 %
IPL’s tax benefit riders
(7.8
)
 
(8.7
)
 
(19.4
)
 
(20.7
)
 
—

 
—

Effect of rate-making on property-related differences
(7.5
)
 
(6.8
)
 
(17.9
)
 
(15.2
)
 
(1.7
)
 
(0.8
)
Production tax credits
(5.9
)
 
(6.3
)
 
(6.6
)
 
(6.7
)
 
(7.0
)
 
(6.5
)
Other items, net
1.0

 
4.5

 
(1.3
)
 
5.9

 
4.7

 
4.8

Overall income tax rate
14.8
%
 
17.7
%
 
(10.2
%)
 
(1.7
%)
 
31.0
%
 
32.5
%
Summary Of Tax Credit Carryforwards
At March 31, 2017, carryforwards and expiration dates were estimated as follows (in millions):
 
Range of Expiration Dates
 
Alliant Energy
 
IPL
 
WPL
Federal net operating losses
2030-2037
 

$633

 

$315

 

$217

State net operating losses
2018-2037
 
696

 
13

 
2

Federal tax credits
2022-2037
 
284

 
104

 
118