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Income Taxes (Tables) | 9 Months Ended
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Sep. 30, 2014
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 September 30 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Statutory federal income tax rate | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | %
IPL’s tax benefit riders | (13.0 | ) |  | (12.9 | ) |  | (39.2 | ) |  | (38.9 | ) |  | — |  |  | — |
Effect of rate-making on property-related differences | (8.6 | ) |  | (6.2 | ) |  | (22.4 | ) |  | (16.5 | ) |  | (0.8 | ) |  | (1.4 | )
Production tax credits | (6.8 | ) |  | (7.7 | ) |  | (9.3 | ) |  | (10.6 | ) |  | (6.2 | ) |  | (6.6 | )
Other items, net | 0.7 |  |  | 1.6 |  |  | 2.2 |  |  | 0.4 |  |  | — |  |  | 3.7 |
Overall income tax rate | 7.3 | % |  | 9.8 | % |  | (33.7 | %) |  | (30.6 | %) |  | 28.0 | % |  | 30.7 | %
| Alliant Energy |  | IPL |  | WPL
Nine Months Ended September 30 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Statutory federal income tax rate | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | %
IPL’s tax benefit riders | (12.4 | ) |  | (12.6 | ) |  | (36.5 | ) |  | (37.8 | ) |  | — |  |  | — |
Effect of rate-making on property-related differences | (6.7 | ) |  | (5.9 | ) |  | (18.4 | ) |  | (16.1 | ) |  | (0.7 | ) |  | (0.8 | )
Production tax credits | (6.6 | ) |  | (7.7 | ) |  | (8.8 | ) |  | (10.4 | ) |  | (6.2 | ) |  | (6.9 | )
Other items, net | 2.9 |  |  | 2.6 |  |  | 3.2 |  |  | 0.8 |  |  | 3.0 |  |  | 4.4 |
Overall income tax rate | 12.2 | % |  | 11.4 | % |  | (25.5 | %) |  | (28.5 | %) |  | 31.1 | % |  | 31.7 | %
Production Tax Credits (Net Of State Tax Impacts) | For the three and nine months ended September 30, details regarding production tax credits (net of state tax impacts) related to various wind projects are as follows (dollars in millions):
| End of Production |  | Nameplate |  | Three Months |  | Nine Months
| Tax Credit Generation |  | Capacity in MW |  | 2014 |  | 2013 |  | 2014 |  | 2013
Cedar Ridge (WPL) | December 2018 |  | 68 |  |  |  | $0.6 |  |  |  | $0.6 |  |  |  | $2.8 |  |  |  | $2.9 |
Bent Tree - Phase I (WPL) | February 2021 |  | 201 |  |  | 2.0 |  |  | 2.2 |  |  | 9.4 |  |  | 9.2 |
Subtotal (WPL) |  |  |  |  | 2.6 |  |  | 2.8 |  |  | 12.2 |  |  | 12.1 |
Whispering Willow - East (IPL) | December 2019 |  | 200 |  |  | 2.0 |  |  | 2.3 |  |  | 9.8 |  |  | 10.3 |
|  |  |  |  |  | $4.6 |  |  |  | $5.1 |  |  |  | $22.0 |  |  |  | $22.4 |
Summary Of Tax Credit Carryforwards | At September 30, 2014, tax carryforwards and associated deferred tax assets and expiration dates were estimated as follows (dollars in millions):
Alliant Energy | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $710 |  |  |  | $244 |  |  | 2029
State net operating losses | 744 |  |  | 37 |  |  | 2018
Federal tax credits | 193 |  |  | 190 |  |  | 2022
|  |  |  | $471 |  |  |
IPL | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $310 |  |  |  | $106 |  |  | 2029
State net operating losses | 217 |  |  | 11 |  |  | 2018
Federal tax credits | 64 |  |  | 63 |  |  | 2022
|  |  |  | $180 |  |  |
WPL | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $305 |  |  |  | $105 |  |  | 2029
State net operating losses | 116 |  |  | 6 |  |  | 2018
Federal tax credits | 71 |  |  | 69 |  |  | 2022
|  |  |  | $180 |  |  |
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 September 30 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Statutory federal income tax rate | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | %
IPL’s tax benefit riders | (13.0 | ) |  | (12.9 | ) |  | (39.2 | ) |  | (38.9 | ) |  | — |  |  | — |
Effect of rate-making on property-related differences | (8.6 | ) |  | (6.2 | ) |  | (22.4 | ) |  | (16.5 | ) |  | (0.8 | ) |  | (1.4 | )
Production tax credits | (6.8 | ) |  | (7.7 | ) |  | (9.3 | ) |  | (10.6 | ) |  | (6.2 | ) |  | (6.6 | )
Other items, net | 0.7 |  |  | 1.6 |  |  | 2.2 |  |  | 0.4 |  |  | — |  |  | 3.7 |
Overall income tax rate | 7.3 | % |  | 9.8 | % |  | (33.7 | %) |  | (30.6 | %) |  | 28.0 | % |  | 30.7 | %
| Alliant Energy |  | IPL |  | WPL
Nine Months Ended September 30 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Statutory federal income tax rate | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | %
IPL’s tax benefit riders | (12.4 | ) |  | (12.6 | ) |  | (36.5 | ) |  | (37.8 | ) |  | — |  |  | — |
Effect of rate-making on property-related differences | (6.7 | ) |  | (5.9 | ) |  | (18.4 | ) |  | (16.1 | ) |  | (0.7 | ) |  | (0.8 | )
Production tax credits | (6.6 | ) |  | (7.7 | ) |  | (8.8 | ) |  | (10.4 | ) |  | (6.2 | ) |  | (6.9 | )
Other items, net | 2.9 |  |  | 2.6 |  |  | 3.2 |  |  | 0.8 |  |  | 3.0 |  |  | 4.4 |
Overall income tax rate | 12.2 | % |  | 11.4 | % |  | (25.5 | %) |  | (28.5 | %) |  | 31.1 | % |  | 31.7 | %
Production Tax Credits (Net Of State Tax Impacts) | For the three and nine months ended September 30, details regarding production tax credits (net of state tax impacts) related to various wind projects are as follows (dollars in millions):
| End of Production |  | Nameplate |  | Three Months |  | Nine Months
| Tax Credit Generation |  | Capacity in MW |  | 2014 |  | 2013 |  | 2014 |  | 2013
Cedar Ridge (WPL) | December 2018 |  | 68 |  |  |  | $0.6 |  |  |  | $0.6 |  |  |  | $2.8 |  |  |  | $2.9 |
Bent Tree - Phase I (WPL) | February 2021 |  | 201 |  |  | 2.0 |  |  | 2.2 |  |  | 9.4 |  |  | 9.2 |
Subtotal (WPL) |  |  |  |  | 2.6 |  |  | 2.8 |  |  | 12.2 |  |  | 12.1 |
Whispering Willow - East (IPL) | December 2019 |  | 200 |  |  | 2.0 |  |  | 2.3 |  |  | 9.8 |  |  | 10.3 |
|  |  |  |  |  | $4.6 |  |  |  | $5.1 |  |  |  | $22.0 |  |  |  | $22.4 |
Summary Of Tax Credit Carryforwards | At September 30, 2014, tax carryforwards and associated deferred tax assets and expiration dates were estimated as follows (dollars in millions):
Alliant Energy | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $710 |  |  |  | $244 |  |  | 2029
State net operating losses | 744 |  |  | 37 |  |  | 2018
Federal tax credits | 193 |  |  | 190 |  |  | 2022
|  |  |  | $471 |  |  |
IPL | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $310 |  |  |  | $106 |  |  | 2029
State net operating losses | 217 |  |  | 11 |  |  | 2018
Federal tax credits | 64 |  |  | 63 |  |  | 2022
|  |  |  | $180 |  |  |
WPL | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $305 |  |  |  | $105 |  |  | 2029
State net operating losses | 116 |  |  | 6 |  |  | 2018
Federal tax credits | 71 |  |  | 69 |  |  | 2022
|  |  |  | $180 |  |  |
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 September 30 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Statutory federal income tax rate | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | %
IPL’s tax benefit riders | (13.0 | ) |  | (12.9 | ) |  | (39.2 | ) |  | (38.9 | ) |  | — |  |  | — |
Effect of rate-making on property-related differences | (8.6 | ) |  | (6.2 | ) |  | (22.4 | ) |  | (16.5 | ) |  | (0.8 | ) |  | (1.4 | )
Production tax credits | (6.8 | ) |  | (7.7 | ) |  | (9.3 | ) |  | (10.6 | ) |  | (6.2 | ) |  | (6.6 | )
Other items, net | 0.7 |  |  | 1.6 |  |  | 2.2 |  |  | 0.4 |  |  | — |  |  | 3.7 |
Overall income tax rate | 7.3 | % |  | 9.8 | % |  | (33.7 | %) |  | (30.6 | %) |  | 28.0 | % |  | 30.7 | %
| Alliant Energy |  | IPL |  | WPL
Nine Months Ended September 30 | 2014 |  | 2013 |  | 2014 |  | 2013 |  | 2014 |  | 2013
Statutory federal income tax rate | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | % |  | 35.0 | %
IPL’s tax benefit riders | (12.4 | ) |  | (12.6 | ) |  | (36.5 | ) |  | (37.8 | ) |  | — |  |  | — |
Effect of rate-making on property-related differences | (6.7 | ) |  | (5.9 | ) |  | (18.4 | ) |  | (16.1 | ) |  | (0.7 | ) |  | (0.8 | )
Production tax credits | (6.6 | ) |  | (7.7 | ) |  | (8.8 | ) |  | (10.4 | ) |  | (6.2 | ) |  | (6.9 | )
Other items, net | 2.9 |  |  | 2.6 |  |  | 3.2 |  |  | 0.8 |  |  | 3.0 |  |  | 4.4 |
Overall income tax rate | 12.2 | % |  | 11.4 | % |  | (25.5 | %) |  | (28.5 | %) |  | 31.1 | % |  | 31.7 | %
Production Tax Credits (Net Of State Tax Impacts) | For the three and nine months ended September 30, details regarding production tax credits (net of state tax impacts) related to various wind projects are as follows (dollars in millions):
| End of Production |  | Nameplate |  | Three Months |  | Nine Months
| Tax Credit Generation |  | Capacity in MW |  | 2014 |  | 2013 |  | 2014 |  | 2013
Cedar Ridge (WPL) | December 2018 |  | 68 |  |  |  | $0.6 |  |  |  | $0.6 |  |  |  | $2.8 |  |  |  | $2.9 |
Bent Tree - Phase I (WPL) | February 2021 |  | 201 |  |  | 2.0 |  |  | 2.2 |  |  | 9.4 |  |  | 9.2 |
Subtotal (WPL) |  |  |  |  | 2.6 |  |  | 2.8 |  |  | 12.2 |  |  | 12.1 |
Whispering Willow - East (IPL) | December 2019 |  | 200 |  |  | 2.0 |  |  | 2.3 |  |  | 9.8 |  |  | 10.3 |
|  |  |  |  |  | $4.6 |  |  |  | $5.1 |  |  |  | $22.0 |  |  |  | $22.4 |
Summary Of Tax Credit Carryforwards | At September 30, 2014, tax carryforwards and associated deferred tax assets and expiration dates were estimated as follows (dollars in millions):
Alliant Energy | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $710 |  |  |  | $244 |  |  | 2029
State net operating losses | 744 |  |  | 37 |  |  | 2018
Federal tax credits | 193 |  |  | 190 |  |  | 2022
|  |  |  | $471 |  |  |
IPL | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $310 |  |  |  | $106 |  |  | 2029
State net operating losses | 217 |  |  | 11 |  |  | 2018
Federal tax credits | 64 |  |  | 63 |  |  | 2022
|  |  |  | $180 |  |  |
WPL | Carryforward Amount |  | Deferred Tax Assets |  | Earliest Expiration Date
Federal net operating losses |  | $305 |  |  |  | $105 |  |  | 2029
State net operating losses | 116 |  |  | 6 |  |  | 2018
Federal tax credits | 71 |  |  | 69 |  |  | 2022
|  |  |  | $180 |  |  |

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- Definition Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319 + Details
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