Income Taxes

6 Months Ended

Jun. 30, 2012

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 effective income tax rates for Alliant Energy, IPL and WPL differ from the federal statutory rate of 35% generally due to effects of enacted tax legislation, utility rate-making, including the tax benefit rider, tax credits, state income taxes and certain non-deductible expenses. Changes in state apportionment rates caused by the planned sale of Alliant Energy’s RMT business also impacted the effective income tax rates for the six months ended June 30, 2012 for Alliant Energy, IPL and WPL. The effective income tax rates shown in the following table for the three and six months ended June 30 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Three Months				Six Months
	2012		2011		2012		2011
Alliant Energy	19.5	%	(25.9	%)	28.3	%	7.8	%
IPL	(12.0	%)	(233.3	%)	22.6	%	3.4	%
WPL	34.6	%	31.1	%	39.4	%	32.0	%

State Apportionment - 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 group, including both its regulated operations and its non-regulated operations. In the first quarter of 2012, Alliant Energy, IPL and WPL recorded $15.2 million, $8.1 million and $7.0 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. These income tax expense amounts recognized in the first quarter of 2012 increased Alliant Energy’s, IPL’s and WPL’s effective income tax rates for continuing operations for the six months ended June 30, 2012 by 9.7%, 34.6% and 6.2%, respectively.

IPL’s Tax Benefit Rider - In January 2011, the IUB approved a tax benefit rider proposed by IPL, which utilizes tax-related regulatory liabilities to credit bills of Iowa retail electric customers beginning in February 2011 to help offset the impact of recent rate increases on such customers. These regulatory liabilities are related to tax benefits from tax accounting method changes for repairs, mixed service costs and allocation of insurance proceeds from the floods in 2008. Alliant Energy’s and IPL’s effective income tax rates for the three and six months ended June 30, 2012 and 2011 include the impact of reducing income tax expense with offsetting reductions to regulatory liabilities as a result of implementing the tax benefit rider. Tax benefit rider-related regulatory liabilities of $20 million and $40 million for the three and six months ended June 30, 2012, and $17 million and $24 million for the three and six months ended June 30, 2011, respectively, were used to credit IPL’s Iowa retail electric customers’ bills. The tax impacts of the tax benefit rider are currently expected to decrease Alliant Energy’s and IPL’s 2012 annual effective income tax rates for continuing operations by 11.9% and 35.5%, respectively. The tax impacts of the tax benefit rider decreased Alliant Energy’s effective income tax rates for continuing operations by 7.8% and 8.6% for the three and six months ended June 30, 2011, respectively, and decreased IPL’s effective income tax rates by 21.9% for the six months ended June 30, 2011. The impacts of the tax benefit rider on the effective tax rate for the three months ended June 30, 2011 for IPL is not meaningful given the impact of IPL’s low income before income taxes for such period.

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 six months ended June 30, production tax credits (net of state tax impacts) resulting from these wind projects were as follows (in millions):

	Three Months				Six Months
	2012		2011		2012		2011
Cedar Ridge (WPL)		$1.0		$1.1		$2.3		$2.6
Bent Tree - Phase I (WPL)	2.7		2.8		4.2		5.3
Subtotal (WPL)	3.7		3.9		6.5		7.9
Whispering Willow - East (IPL)	3.1		3.6		6.7		6.4
		$6.8		$7.5		$13.2		$14.3

Wisconsin Tax Legislation - In June 2011, the 2011 Wisconsin Act 32 (Act 32) was enacted. The most significant provision of Act 32 for Alliant Energy authorizes combined groups to share net operating loss carryforwards that were incurred by group members prior to January 1, 2009 and utilize these shared net operating losses over 20 years beginning after December 31, 2011. Based on this provision of Act 32, Alliant Energy anticipated its Wisconsin combined group will be able to fully utilize $368 million of Wisconsin net operating losses incurred by Alliant Energy and Resources prior to January 1, 2009 to offset future taxable income and therefore reversed previously recorded deferred tax asset valuation allowances related to state net operating loss carryforwards of $19 million in the second quarter of 2011. The income tax benefits recognized in the second quarter of 2011 from Act 32 decreased Alliant Energy’s effective income tax rates for continuing operations by 43.7% and 13.1% for the second quarter and first half of 2011, respectively.

Deferred Tax Assets and Liabilities - For the six months ended June 30, 2012, Alliant Energy’s, IPL’s and WPL’s current deferred tax assets increased $60.1 million, $21.4 million and $37.9 million, respectively, and Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $143.9 million, $55.7 million and $82.0 million, respectively. These increases were primarily due to a transfer of deferred tax assets from non-current to current caused by an increase in the amount of federal and state net operating loss carryforwards expected to be utilized during the next 12 months. The increase in non-current deferred tax liabilities was also due to property-related temporary differences recorded during the six months ended June 30, 2012 from bonus depreciation deductions available in 2012.

Bonus Depreciation Deductions - In 2010, the Small Business Jobs Act of 2010 (SBJA) and the Tax Relief, Unemployment Insurance Reauthorization and Job Creation Act of 2010 (the Act) were enacted. The most significant provisions of the SBJA and the Act for Alliant Energy, IPL and WPL are related to the extension of bonus depreciation deductions for certain expenditures for property that are placed in service through December 31, 2012. Based on capital projects expected to be placed into service in 2012, Alliant Energy currently estimates its total bonus depreciation deductions to be claimed in its 2012 federal income tax return will be approximately $418 million ($114 million for IPL, $203 million for WPL and $101 million for Resources).

Carryforwards - At June 30, 2012, tax carryforwards and associated deferred tax assets and expiration dates were estimated as follows (in millions):

Alliant Energy	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$1,026			$352		2028
Federal net operating losses offset - uncertain tax positions	(57		)	(20		)
State net operating losses	756			39			2014
State net operating losses offset - uncertain tax positions	(27		)	(2		)
Federal tax credits	122			121			2022
					$490

IPL	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$472			$162		2028
Federal net operating losses offset - uncertain tax positions	(26		)	(9		)
State net operating losses	171			10			2022
Federal tax credits	32			32			2022
					$195

WPL	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$437			$150		2028
Federal net operating losses offset - uncertain tax positions	(31		)	(11		)
State net operating losses	142			7			2022
State net operating losses offset - uncertain tax positions	(27		)	(2		)
Federal tax credits	33			33			2022
					$177

Uncertain Tax Positions - It is reasonably possible that Alliant Energy, IPL and WPL could have material changes to their unrecognized tax benefits during the next 12 months as a result of the expected issuance in 2012 of revenue procedures clarifying the treatment of repair expenditures for electric generation and gas distribution property. An estimate of the expected changes during the next 12 months cannot be determined at this time.

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 effective income tax rates for Alliant Energy, IPL and WPL differ from the federal statutory rate of 35% generally due to effects of enacted tax legislation, utility rate-making, including the tax benefit rider, tax credits, state income taxes and certain non-deductible expenses. Changes in state apportionment rates caused by the planned sale of Alliant Energy’s RMT business also impacted the effective income tax rates for the six months ended June 30, 2012 for Alliant Energy, IPL and WPL. The effective income tax rates shown in the following table for the three and six months ended June 30 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Three Months				Six Months
	2012		2011		2012		2011
Alliant Energy	19.5	%	(25.9	%)	28.3	%	7.8	%
IPL	(12.0	%)	(233.3	%)	22.6	%	3.4	%
WPL	34.6	%	31.1	%	39.4	%	32.0	%

State Apportionment - 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 group, including both its regulated operations and its non-regulated operations. In the first quarter of 2012, Alliant Energy, IPL and WPL recorded $15.2 million, $8.1 million and $7.0 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. These income tax expense amounts recognized in the first quarter of 2012 increased Alliant Energy’s, IPL’s and WPL’s effective income tax rates for continuing operations for the six months ended June 30, 2012 by 9.7%, 34.6% and 6.2%, respectively.

IPL’s Tax Benefit Rider - In January 2011, the IUB approved a tax benefit rider proposed by IPL, which utilizes tax-related regulatory liabilities to credit bills of Iowa retail electric customers beginning in February 2011 to help offset the impact of recent rate increases on such customers. These regulatory liabilities are related to tax benefits from tax accounting method changes for repairs, mixed service costs and allocation of insurance proceeds from the floods in 2008. Alliant Energy’s and IPL’s effective income tax rates for the three and six months ended June 30, 2012 and 2011 include the impact of reducing income tax expense with offsetting reductions to regulatory liabilities as a result of implementing the tax benefit rider. Tax benefit rider-related regulatory liabilities of $20 million and $40 million for the three and six months ended June 30, 2012, and $17 million and $24 million for the three and six months ended June 30, 2011, respectively, were used to credit IPL’s Iowa retail electric customers’ bills. The tax impacts of the tax benefit rider are currently expected to decrease Alliant Energy’s and IPL’s 2012 annual effective income tax rates for continuing operations by 11.9% and 35.5%, respectively. The tax impacts of the tax benefit rider decreased Alliant Energy’s effective income tax rates for continuing operations by 7.8% and 8.6% for the three and six months ended June 30, 2011, respectively, and decreased IPL’s effective income tax rates by 21.9% for the six months ended June 30, 2011. The impacts of the tax benefit rider on the effective tax rate for the three months ended June 30, 2011 for IPL is not meaningful given the impact of IPL’s low income before income taxes for such period.

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 six months ended June 30, production tax credits (net of state tax impacts) resulting from these wind projects were as follows (in millions):

	Three Months				Six Months
	2012		2011		2012		2011
Cedar Ridge (WPL)		$1.0		$1.1		$2.3		$2.6
Bent Tree - Phase I (WPL)	2.7		2.8		4.2		5.3
Subtotal (WPL)	3.7		3.9		6.5		7.9
Whispering Willow - East (IPL)	3.1		3.6		6.7		6.4
		$6.8		$7.5		$13.2		$14.3

Wisconsin Tax Legislation - In June 2011, the 2011 Wisconsin Act 32 (Act 32) was enacted. The most significant provision of Act 32 for Alliant Energy authorizes combined groups to share net operating loss carryforwards that were incurred by group members prior to January 1, 2009 and utilize these shared net operating losses over 20 years beginning after December 31, 2011. Based on this provision of Act 32, Alliant Energy anticipated its Wisconsin combined group will be able to fully utilize $368 million of Wisconsin net operating losses incurred by Alliant Energy and Resources prior to January 1, 2009 to offset future taxable income and therefore reversed previously recorded deferred tax asset valuation allowances related to state net operating loss carryforwards of $19 million in the second quarter of 2011. The income tax benefits recognized in the second quarter of 2011 from Act 32 decreased Alliant Energy’s effective income tax rates for continuing operations by 43.7% and 13.1% for the second quarter and first half of 2011, respectively.

Deferred Tax Assets and Liabilities - For the six months ended June 30, 2012, Alliant Energy’s, IPL’s and WPL’s current deferred tax assets increased $60.1 million, $21.4 million and $37.9 million, respectively, and Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $143.9 million, $55.7 million and $82.0 million, respectively. These increases were primarily due to a transfer of deferred tax assets from non-current to current caused by an increase in the amount of federal and state net operating loss carryforwards expected to be utilized during the next 12 months. The increase in non-current deferred tax liabilities was also due to property-related temporary differences recorded during the six months ended June 30, 2012 from bonus depreciation deductions available in 2012.

Bonus Depreciation Deductions - In 2010, the Small Business Jobs Act of 2010 (SBJA) and the Tax Relief, Unemployment Insurance Reauthorization and Job Creation Act of 2010 (the Act) were enacted. The most significant provisions of the SBJA and the Act for Alliant Energy, IPL and WPL are related to the extension of bonus depreciation deductions for certain expenditures for property that are placed in service through December 31, 2012. Based on capital projects expected to be placed into service in 2012, Alliant Energy currently estimates its total bonus depreciation deductions to be claimed in its 2012 federal income tax return will be approximately $418 million ($114 million for IPL, $203 million for WPL and $101 million for Resources).

Carryforwards - At June 30, 2012, tax carryforwards and associated deferred tax assets and expiration dates were estimated as follows (in millions):

Alliant Energy	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$1,026			$352		2028
Federal net operating losses offset - uncertain tax positions	(57		)	(20		)
State net operating losses	756			39			2014
State net operating losses offset - uncertain tax positions	(27		)	(2		)
Federal tax credits	122			121			2022
					$490

IPL	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$472			$162		2028
Federal net operating losses offset - uncertain tax positions	(26		)	(9		)
State net operating losses	171			10			2022
Federal tax credits	32			32			2022
					$195

WPL	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$437			$150		2028
Federal net operating losses offset - uncertain tax positions	(31		)	(11		)
State net operating losses	142			7			2022
State net operating losses offset - uncertain tax positions	(27		)	(2		)
Federal tax credits	33			33			2022
					$177

Uncertain Tax Positions - It is reasonably possible that Alliant Energy, IPL and WPL could have material changes to their unrecognized tax benefits during the next 12 months as a result of the expected issuance in 2012 of revenue procedures clarifying the treatment of repair expenditures for electric generation and gas distribution property. An estimate of the expected changes during the next 12 months cannot be determined at this time.

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 effective income tax rates for Alliant Energy, IPL and WPL differ from the federal statutory rate of 35% generally due to effects of enacted tax legislation, utility rate-making, including the tax benefit rider, tax credits, state income taxes and certain non-deductible expenses. Changes in state apportionment rates caused by the planned sale of Alliant Energy’s RMT business also impacted the effective income tax rates for the six months ended June 30, 2012 for Alliant Energy, IPL and WPL. The effective income tax rates shown in the following table for the three and six months ended June 30 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Three Months				Six Months
	2012		2011		2012		2011
Alliant Energy	19.5	%	(25.9	%)	28.3	%	7.8	%
IPL	(12.0	%)	(233.3	%)	22.6	%	3.4	%
WPL	34.6	%	31.1	%	39.4	%	32.0	%

State Apportionment - 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 group, including both its regulated operations and its non-regulated operations. In the first quarter of 2012, Alliant Energy, IPL and WPL recorded $15.2 million, $8.1 million and $7.0 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. These income tax expense amounts recognized in the first quarter of 2012 increased Alliant Energy’s, IPL’s and WPL’s effective income tax rates for continuing operations for the six months ended June 30, 2012 by 9.7%, 34.6% and 6.2%, respectively.

IPL’s Tax Benefit Rider - In January 2011, the IUB approved a tax benefit rider proposed by IPL, which utilizes tax-related regulatory liabilities to credit bills of Iowa retail electric customers beginning in February 2011 to help offset the impact of recent rate increases on such customers. These regulatory liabilities are related to tax benefits from tax accounting method changes for repairs, mixed service costs and allocation of insurance proceeds from the floods in 2008. Alliant Energy’s and IPL’s effective income tax rates for the three and six months ended June 30, 2012 and 2011 include the impact of reducing income tax expense with offsetting reductions to regulatory liabilities as a result of implementing the tax benefit rider. Tax benefit rider-related regulatory liabilities of $20 million and $40 million for the three and six months ended June 30, 2012, and $17 million and $24 million for the three and six months ended June 30, 2011, respectively, were used to credit IPL’s Iowa retail electric customers’ bills. The tax impacts of the tax benefit rider are currently expected to decrease Alliant Energy’s and IPL’s 2012 annual effective income tax rates for continuing operations by 11.9% and 35.5%, respectively. The tax impacts of the tax benefit rider decreased Alliant Energy’s effective income tax rates for continuing operations by 7.8% and 8.6% for the three and six months ended June 30, 2011, respectively, and decreased IPL’s effective income tax rates by 21.9% for the six months ended June 30, 2011. The impacts of the tax benefit rider on the effective tax rate for the three months ended June 30, 2011 for IPL is not meaningful given the impact of IPL’s low income before income taxes for such period.

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 six months ended June 30, production tax credits (net of state tax impacts) resulting from these wind projects were as follows (in millions):

	Three Months				Six Months
	2012		2011		2012		2011
Cedar Ridge (WPL)		$1.0		$1.1		$2.3		$2.6
Bent Tree - Phase I (WPL)	2.7		2.8		4.2		5.3
Subtotal (WPL)	3.7		3.9		6.5		7.9
Whispering Willow - East (IPL)	3.1		3.6		6.7		6.4
		$6.8		$7.5		$13.2		$14.3

Wisconsin Tax Legislation - In June 2011, the 2011 Wisconsin Act 32 (Act 32) was enacted. The most significant provision of Act 32 for Alliant Energy authorizes combined groups to share net operating loss carryforwards that were incurred by group members prior to January 1, 2009 and utilize these shared net operating losses over 20 years beginning after December 31, 2011. Based on this provision of Act 32, Alliant Energy anticipated its Wisconsin combined group will be able to fully utilize $368 million of Wisconsin net operating losses incurred by Alliant Energy and Resources prior to January 1, 2009 to offset future taxable income and therefore reversed previously recorded deferred tax asset valuation allowances related to state net operating loss carryforwards of $19 million in the second quarter of 2011. The income tax benefits recognized in the second quarter of 2011 from Act 32 decreased Alliant Energy’s effective income tax rates for continuing operations by 43.7% and 13.1% for the second quarter and first half of 2011, respectively.

Deferred Tax Assets and Liabilities - For the six months ended June 30, 2012, Alliant Energy’s, IPL’s and WPL’s current deferred tax assets increased $60.1 million, $21.4 million and $37.9 million, respectively, and Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $143.9 million, $55.7 million and $82.0 million, respectively. These increases were primarily due to a transfer of deferred tax assets from non-current to current caused by an increase in the amount of federal and state net operating loss carryforwards expected to be utilized during the next 12 months. The increase in non-current deferred tax liabilities was also due to property-related temporary differences recorded during the six months ended June 30, 2012 from bonus depreciation deductions available in 2012.

Bonus Depreciation Deductions - In 2010, the Small Business Jobs Act of 2010 (SBJA) and the Tax Relief, Unemployment Insurance Reauthorization and Job Creation Act of 2010 (the Act) were enacted. The most significant provisions of the SBJA and the Act for Alliant Energy, IPL and WPL are related to the extension of bonus depreciation deductions for certain expenditures for property that are placed in service through December 31, 2012. Based on capital projects expected to be placed into service in 2012, Alliant Energy currently estimates its total bonus depreciation deductions to be claimed in its 2012 federal income tax return will be approximately $418 million ($114 million for IPL, $203 million for WPL and $101 million for Resources).

Carryforwards - At June 30, 2012, tax carryforwards and associated deferred tax assets and expiration dates were estimated as follows (in millions):

Alliant Energy	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$1,026			$352		2028
Federal net operating losses offset - uncertain tax positions	(57		)	(20		)
State net operating losses	756			39			2014
State net operating losses offset - uncertain tax positions	(27		)	(2		)
Federal tax credits	122			121			2022
					$490

IPL	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$472			$162		2028
Federal net operating losses offset - uncertain tax positions	(26		)	(9		)
State net operating losses	171			10			2022
Federal tax credits	32			32			2022
					$195

WPL	Carryforward Amount			Deferred Tax Assets			Earliest Expiration Date
Federal net operating losses		$437			$150		2028
Federal net operating losses offset - uncertain tax positions	(31		)	(11		)
State net operating losses	142			7			2022
State net operating losses offset - uncertain tax positions	(27		)	(2		)
Federal tax credits	33			33			2022
					$177

Uncertain Tax Positions - It is reasonably possible that Alliant Energy, IPL and WPL could have material changes to their unrecognized tax benefits during the next 12 months as a result of the expected issuance in 2012 of revenue procedures clarifying the treatment of repair expenditures for electric generation and gas distribution property. An estimate of the expected changes during the next 12 months cannot be determined at this time.