Income Taxes

9 Months Ended

Sep. 30, 2013

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Rates - The provision for income taxes for earnings from continuing operations is based on an estimated annual effective income tax rate that excludes the impact of significant unusual or infrequently occurring items, discontinued operations or extraordinary items. The overall income tax rates shown in the following table for the three and nine months ended September 30 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	2013		2012		2013		2012		2013		2012
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%
IPL’s tax benefit riders	(12.9	)	(10.3	)	(38.9	)	(34.2	)	—		—
Production tax credits	(7.7	)	(5.5	)	(10.6	)	(8.6	)	(6.6	)	(4.3	)
Effect of rate-making on property-related differences	(6.2	)	(4.7	)	(16.5	)	(11.2	)	(1.4	)	(1.1	)
Other items, net	1.6		5.9		0.4		6.4		3.7		5.9
Overall income tax rate	9.8	%	20.4	%	(30.6	%)	(12.6	%)	30.7	%	35.5	%

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2013		2012		2013		2012		2013		2012
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%
IPL’s tax benefit riders	(12.6	)	(11.0	)	(37.8	)	(34.5	)	—		—
Production tax credits	(7.7	)	(6.0	)	(10.4	)	(8.6	)	(6.9	)	(5.5	)
Effect of rate-making on property-related differences	(5.9	)	(4.3	)	(16.1	)	(10.6	)	(0.8	)	(1.5	)
State apportionment change due to planned sale of RMT	—		4.3		—		6.9		—		3.5
Other items, net	2.6		6.0		0.8		6.2		4.4		6.2
Overall income tax rate	11.4	%	24.0	%	(28.5	%)	(5.6	%)	31.7	%	37.7	%

IPL’s tax benefit riders - Alliant Energy’s and IPL’s effective income tax rates include the impact of reducing income tax expense with offsetting reductions to regulatory liabilities as a result of implementing the tax benefit riders. Refer to Note 1(b) for additional details of IPL’s tax benefit riders.

Production tax credits - Alliant Energy has three wind projects that are currently generating production tax credits: WPL’s 68 MW Cedar Ridge wind project, which began generating electricity in late 2008; IPL’s 200 MW Whispering Willow - East wind project, which began generating electricity in late 2009; and WPL’s 200 MW Bent Tree - Phase I wind project, which began generating electricity in late 2010. For the three and nine months ended September 30, production tax credits (net of state tax impacts) resulting from these wind projects are included in the table below (in millions). Production tax credits for Bent Tree - Phase I and Whispering Willow - East increased for the three- and nine-month periods primarily due to higher levels of electricity output generated by the wind projects.

	Three Months				Nine Months
	2013		2012		2013		2012
Cedar Ridge (WPL)		$0.6		$0.7		$2.9		$3.0
Bent Tree - Phase I (WPL)	2.2		1.8		9.2		6.0
Subtotal (WPL)	2.8		2.5		12.1		9.0
Whispering Willow - East (IPL)	2.3		2.0		10.3		8.7
		$5.1		$4.5		$22.4		$17.7

Effect of rate-making on property-related differences - Alliant Energy’s and IPL’s effective income tax rates are impacted by certain property-related differences for which deferred tax is not recognized in the income statement pursuant to rate-making principles, substantially all of which relates to IPL. The primary factor contributing to the increase in the current tax benefits recorded for the effect of rate-making on property-related differences during the three and nine months ended September 30, 2013 was repair expenditures at IPL.

State apportionment change due to planned sale of RMT - Alliant Energy, IPL and WPL utilize state apportionment projections to record their deferred tax assets and liabilities each reporting period. Deferred tax assets and liabilities for temporary differences between the tax basis of assets and liabilities and the amounts reported in the condensed consolidated financial statements are recorded utilizing currently enacted tax rates and estimates of future state apportionment rates expected to be in effect at the time the temporary differences reverse. These state apportionment projections are most significantly impacted by the estimated amount of revenues expected in the future from each state jurisdiction for Alliant Energy’s consolidated tax groups, including both its regulated and its non-regulated operations. In the first quarter of 2012, Alliant Energy, IPL and WPL recorded $15 million, $8 million and $7 million, respectively, of deferred income tax expense due to changes in state apportionment projections caused by the planned sale of Alliant Energy’s RMT business.

Deferred Tax Assets and Liabilities - For the nine months ended September 30, 2013, Alliant Energy’s and WPL’s current deferred tax assets decreased $39.0 million and $40.7 million, respectively. The decrease in current deferred tax assets reflects a decrease in the estimated amount of net operating losses expected to be utilized in the next 12 months primarily due to the extension of bonus depreciation deductions in the first quarter of 2013 with the enactment of the ATR Act in January 2013.

For the nine months ended September 30, 2013, Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $129.7 million, $73.7 million and $41.3 million, respectively. These increases were primarily due to property-related differences resulting from bonus depreciation deductions and the effect of rate-making on property-related differences recorded during the nine months ended September 30, 2013. Alliant Energy’s and WPL’s increases were partially offset by the decrease of certain deferred tax assets discussed above, which decreased Alliant Energy’s and WPL’s non-current deferred tax liabilities.

Carryforwards - At September 30, 2013, 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		$775		$266	2029
State net operating losses	753		39		2018
Federal tax credits	161		159		2022
				$464

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$344		$118	2029
State net operating losses	189		10		2018
Federal tax credits	49		48		2022
				$176

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$321		$110	2029
State net operating losses	177		9		2018
Federal tax credits	54		53		2022
				$172

Uncertain Tax Positions - In 2013, statutes of limitations will expire for Alliant Energy’s, IPL’s and WPL’s tax returns in multiple state jurisdictions. The expiration of the statutes of limitations will not have any impact on Alliant Energy’s, IPL’s and WPL’s uncertain tax positions in 2013. As of September 30, 2013, Alliant Energy, IPL and WPL do not expect to have material changes to their unrecognized tax benefits during the next 12 months.

IPL [Member]

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Rates - The provision for income taxes for earnings from continuing operations is based on an estimated annual effective income tax rate that excludes the impact of significant unusual or infrequently occurring items, discontinued operations or extraordinary items. The overall income tax rates shown in the following table for the three and nine months ended September 30 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	2013		2012		2013		2012		2013		2012
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%
IPL’s tax benefit riders	(12.9	)	(10.3	)	(38.9	)	(34.2	)	—		—
Production tax credits	(7.7	)	(5.5	)	(10.6	)	(8.6	)	(6.6	)	(4.3	)
Effect of rate-making on property-related differences	(6.2	)	(4.7	)	(16.5	)	(11.2	)	(1.4	)	(1.1	)
Other items, net	1.6		5.9		0.4		6.4		3.7		5.9
Overall income tax rate	9.8	%	20.4	%	(30.6	%)	(12.6	%)	30.7	%	35.5	%

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2013		2012		2013		2012		2013		2012
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%
IPL’s tax benefit riders	(12.6	)	(11.0	)	(37.8	)	(34.5	)	—		—
Production tax credits	(7.7	)	(6.0	)	(10.4	)	(8.6	)	(6.9	)	(5.5	)
Effect of rate-making on property-related differences	(5.9	)	(4.3	)	(16.1	)	(10.6	)	(0.8	)	(1.5	)
State apportionment change due to planned sale of RMT	—		4.3		—		6.9		—		3.5
Other items, net	2.6		6.0		0.8		6.2		4.4		6.2
Overall income tax rate	11.4	%	24.0	%	(28.5	%)	(5.6	%)	31.7	%	37.7	%

IPL’s tax benefit riders - Alliant Energy’s and IPL’s effective income tax rates include the impact of reducing income tax expense with offsetting reductions to regulatory liabilities as a result of implementing the tax benefit riders. Refer to Note 1(b) for additional details of IPL’s tax benefit riders.

Production tax credits - Alliant Energy has three wind projects that are currently generating production tax credits: WPL’s 68 MW Cedar Ridge wind project, which began generating electricity in late 2008; IPL’s 200 MW Whispering Willow - East wind project, which began generating electricity in late 2009; and WPL’s 200 MW Bent Tree - Phase I wind project, which began generating electricity in late 2010. For the three and nine months ended September 30, production tax credits (net of state tax impacts) resulting from these wind projects are included in the table below (in millions). Production tax credits for Bent Tree - Phase I and Whispering Willow - East increased for the three- and nine-month periods primarily due to higher levels of electricity output generated by the wind projects.

	Three Months				Nine Months
	2013		2012		2013		2012
Cedar Ridge (WPL)		$0.6		$0.7		$2.9		$3.0
Bent Tree - Phase I (WPL)	2.2		1.8		9.2		6.0
Subtotal (WPL)	2.8		2.5		12.1		9.0
Whispering Willow - East (IPL)	2.3		2.0		10.3		8.7
		$5.1		$4.5		$22.4		$17.7

Effect of rate-making on property-related differences - Alliant Energy’s and IPL’s effective income tax rates are impacted by certain property-related differences for which deferred tax is not recognized in the income statement pursuant to rate-making principles, substantially all of which relates to IPL. The primary factor contributing to the increase in the current tax benefits recorded for the effect of rate-making on property-related differences during the three and nine months ended September 30, 2013 was repair expenditures at IPL.

State apportionment change due to planned sale of RMT - Alliant Energy, IPL and WPL utilize state apportionment projections to record their deferred tax assets and liabilities each reporting period. Deferred tax assets and liabilities for temporary differences between the tax basis of assets and liabilities and the amounts reported in the condensed consolidated financial statements are recorded utilizing currently enacted tax rates and estimates of future state apportionment rates expected to be in effect at the time the temporary differences reverse. These state apportionment projections are most significantly impacted by the estimated amount of revenues expected in the future from each state jurisdiction for Alliant Energy’s consolidated tax groups, including both its regulated and its non-regulated operations. In the first quarter of 2012, Alliant Energy, IPL and WPL recorded $15 million, $8 million and $7 million, respectively, of deferred income tax expense due to changes in state apportionment projections caused by the planned sale of Alliant Energy’s RMT business.

Deferred Tax Assets and Liabilities - For the nine months ended September 30, 2013, Alliant Energy’s and WPL’s current deferred tax assets decreased $39.0 million and $40.7 million, respectively. The decrease in current deferred tax assets reflects a decrease in the estimated amount of net operating losses expected to be utilized in the next 12 months primarily due to the extension of bonus depreciation deductions in the first quarter of 2013 with the enactment of the ATR Act in January 2013.

For the nine months ended September 30, 2013, Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $129.7 million, $73.7 million and $41.3 million, respectively. These increases were primarily due to property-related differences resulting from bonus depreciation deductions and the effect of rate-making on property-related differences recorded during the nine months ended September 30, 2013. Alliant Energy’s and WPL’s increases were partially offset by the decrease of certain deferred tax assets discussed above, which decreased Alliant Energy’s and WPL’s non-current deferred tax liabilities.

Carryforwards - At September 30, 2013, 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		$775		$266	2029
State net operating losses	753		39		2018
Federal tax credits	161		159		2022
				$464

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$344		$118	2029
State net operating losses	189		10		2018
Federal tax credits	49		48		2022
				$176

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$321		$110	2029
State net operating losses	177		9		2018
Federal tax credits	54		53		2022
				$172

Uncertain Tax Positions - In 2013, statutes of limitations will expire for Alliant Energy’s, IPL’s and WPL’s tax returns in multiple state jurisdictions. The expiration of the statutes of limitations will not have any impact on Alliant Energy’s, IPL’s and WPL’s uncertain tax positions in 2013. As of September 30, 2013, Alliant Energy, IPL and WPL do not expect to have material changes to their unrecognized tax benefits during the next 12 months.

WPL [Member]

Income Tax [Line Items]

Income Taxes

INCOME TAXES

Income Tax Rates - The provision for income taxes for earnings from continuing operations is based on an estimated annual effective income tax rate that excludes the impact of significant unusual or infrequently occurring items, discontinued operations or extraordinary items. The overall income tax rates shown in the following table for the three and nine months ended September 30 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	2013		2012		2013		2012		2013		2012
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%
IPL’s tax benefit riders	(12.9	)	(10.3	)	(38.9	)	(34.2	)	—		—
Production tax credits	(7.7	)	(5.5	)	(10.6	)	(8.6	)	(6.6	)	(4.3	)
Effect of rate-making on property-related differences	(6.2	)	(4.7	)	(16.5	)	(11.2	)	(1.4	)	(1.1	)
Other items, net	1.6		5.9		0.4		6.4		3.7		5.9
Overall income tax rate	9.8	%	20.4	%	(30.6	%)	(12.6	%)	30.7	%	35.5	%

	Alliant Energy				IPL				WPL
Nine Months Ended September 30	2013		2012		2013		2012		2013		2012
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%	35.0	%
IPL’s tax benefit riders	(12.6	)	(11.0	)	(37.8	)	(34.5	)	—		—
Production tax credits	(7.7	)	(6.0	)	(10.4	)	(8.6	)	(6.9	)	(5.5	)
Effect of rate-making on property-related differences	(5.9	)	(4.3	)	(16.1	)	(10.6	)	(0.8	)	(1.5	)
State apportionment change due to planned sale of RMT	—		4.3		—		6.9		—		3.5
Other items, net	2.6		6.0		0.8		6.2		4.4		6.2
Overall income tax rate	11.4	%	24.0	%	(28.5	%)	(5.6	%)	31.7	%	37.7	%

IPL’s tax benefit riders - Alliant Energy’s and IPL’s effective income tax rates include the impact of reducing income tax expense with offsetting reductions to regulatory liabilities as a result of implementing the tax benefit riders. Refer to Note 1(b) for additional details of IPL’s tax benefit riders.

Production tax credits - Alliant Energy has three wind projects that are currently generating production tax credits: WPL’s 68 MW Cedar Ridge wind project, which began generating electricity in late 2008; IPL’s 200 MW Whispering Willow - East wind project, which began generating electricity in late 2009; and WPL’s 200 MW Bent Tree - Phase I wind project, which began generating electricity in late 2010. For the three and nine months ended September 30, production tax credits (net of state tax impacts) resulting from these wind projects are included in the table below (in millions). Production tax credits for Bent Tree - Phase I and Whispering Willow - East increased for the three- and nine-month periods primarily due to higher levels of electricity output generated by the wind projects.

	Three Months				Nine Months
	2013		2012		2013		2012
Cedar Ridge (WPL)		$0.6		$0.7		$2.9		$3.0
Bent Tree - Phase I (WPL)	2.2		1.8		9.2		6.0
Subtotal (WPL)	2.8		2.5		12.1		9.0
Whispering Willow - East (IPL)	2.3		2.0		10.3		8.7
		$5.1		$4.5		$22.4		$17.7

Effect of rate-making on property-related differences - Alliant Energy’s and IPL’s effective income tax rates are impacted by certain property-related differences for which deferred tax is not recognized in the income statement pursuant to rate-making principles, substantially all of which relates to IPL. The primary factor contributing to the increase in the current tax benefits recorded for the effect of rate-making on property-related differences during the three and nine months ended September 30, 2013 was repair expenditures at IPL.

State apportionment change due to planned sale of RMT - Alliant Energy, IPL and WPL utilize state apportionment projections to record their deferred tax assets and liabilities each reporting period. Deferred tax assets and liabilities for temporary differences between the tax basis of assets and liabilities and the amounts reported in the condensed consolidated financial statements are recorded utilizing currently enacted tax rates and estimates of future state apportionment rates expected to be in effect at the time the temporary differences reverse. These state apportionment projections are most significantly impacted by the estimated amount of revenues expected in the future from each state jurisdiction for Alliant Energy’s consolidated tax groups, including both its regulated and its non-regulated operations. In the first quarter of 2012, Alliant Energy, IPL and WPL recorded $15 million, $8 million and $7 million, respectively, of deferred income tax expense due to changes in state apportionment projections caused by the planned sale of Alliant Energy’s RMT business.

Deferred Tax Assets and Liabilities - For the nine months ended September 30, 2013, Alliant Energy’s and WPL’s current deferred tax assets decreased $39.0 million and $40.7 million, respectively. The decrease in current deferred tax assets reflects a decrease in the estimated amount of net operating losses expected to be utilized in the next 12 months primarily due to the extension of bonus depreciation deductions in the first quarter of 2013 with the enactment of the ATR Act in January 2013.

For the nine months ended September 30, 2013, Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $129.7 million, $73.7 million and $41.3 million, respectively. These increases were primarily due to property-related differences resulting from bonus depreciation deductions and the effect of rate-making on property-related differences recorded during the nine months ended September 30, 2013. Alliant Energy’s and WPL’s increases were partially offset by the decrease of certain deferred tax assets discussed above, which decreased Alliant Energy’s and WPL’s non-current deferred tax liabilities.

Carryforwards - At September 30, 2013, 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		$775		$266	2029
State net operating losses	753		39		2018
Federal tax credits	161		159		2022
				$464

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$344		$118	2029
State net operating losses	189		10		2018
Federal tax credits	49		48		2022
				$176

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$321		$110	2029
State net operating losses	177		9		2018
Federal tax credits	54		53		2022
				$172

Uncertain Tax Positions - In 2013, statutes of limitations will expire for Alliant Energy’s, IPL’s and WPL’s tax returns in multiple state jurisdictions. The expiration of the statutes of limitations will not have any impact on Alliant Energy’s, IPL’s and WPL’s uncertain tax positions in 2013. As of September 30, 2013, Alliant Energy, IPL and WPL do not expect to have material changes to their unrecognized tax benefits during the next 12 months.