Income Taxes

6 Months Ended

Jun. 30, 2014

Income Taxes [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 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy				IPL				WPL
Three Months Ended June 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	(11.9	)	(11.7	)	(36.6	)	(33.3	)	—		—
Production tax credits	(6.1	)	(7.9	)	(8.0	)	(10.5	)	(5.8	)	(7.2	)
Effect of rate-making on property-related differences	(4.8	)	(6.4	)	(14.4	)	(17.4	)	(0.2	)	(0.5	)
Other items, net	4.8		4.3		4.6		1.5		5.0		5.8
Overall income tax rate	17.0	%	13.3	%	(19.4	%)	(24.7	%)	34.0	%	33.1	%

	Alliant Energy				IPL				WPL
Six Months Ended June 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	(11.9	)	(12.3	)	(32.8	)	(35.6	)	—		—
Production tax credits	(6.5	)	(7.7	)	(8.2	)	(10.1	)	(6.2	)	(7.0	)
Effect of rate-making on property-related differences	(5.1	)	(5.6	)	(13.0	)	(15.5	)	(0.7	)	(0.4	)
Other items, net	4.7		3.6		4.6		1.9		4.9		4.9
Overall income tax rate	16.2	%	13.0	%	(14.4	%)	(24.3	%)	33.0	%	32.5	%

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 IPL’s tax benefit riders. Refer to Note 2 for additional details of the tax benefit riders.

Production tax credits - For the three and six months ended June 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				Six Months
	Tax Credit Generation	Capacity in MW	2014		2013		2014		2013
Cedar Ridge (WPL)	December 2018	68		$1.0		$1.1		$2.2		$2.3
Bent Tree - Phase I (WPL)	February 2021	201	3.2		3.5		7.4		7.0
Subtotal (WPL)			4.2		4.6		9.6		9.3
Whispering Willow - East (IPL)	December 2019	200	3.2		4.1		7.8		8.0
				$7.4		$8.7		$17.4		$17.3

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.

Deferred Tax Assets and Liabilities - For the six months ended June 30, 2014, Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $77.2 million, $57.0 million and $21.1 million, respectively. These increases in non-current deferred tax liabilities were primarily due to property-related differences resulting from accelerated depreciation deductions, qualifying repairs expenditures, a tax accounting method change made for cost of removal expenditures and the effect of rate-making on property-related differences recorded during the six months ended June 30, 2014. Refer to Note 2 for further discussion of the tax accounting method change for cost of removal expenditures.

Carryforwards - At June 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		$721		$248	2029
State net operating losses	747		38		2018
Federal tax credits	188		185		2022
				$471

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$317		$109	2029
State net operating losses	222		11		2018
Federal tax credits	62		61		2022
				$181

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$308		$106	2029
State net operating losses	114		6		2018
Federal tax credits	68		67		2022
				$179

IPL [Member]

Income Taxes [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 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy				IPL				WPL
Three Months Ended June 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	(11.9	)	(11.7	)	(36.6	)	(33.3	)	—		—
Production tax credits	(6.1	)	(7.9	)	(8.0	)	(10.5	)	(5.8	)	(7.2	)
Effect of rate-making on property-related differences	(4.8	)	(6.4	)	(14.4	)	(17.4	)	(0.2	)	(0.5	)
Other items, net	4.8		4.3		4.6		1.5		5.0		5.8
Overall income tax rate	17.0	%	13.3	%	(19.4	%)	(24.7	%)	34.0	%	33.1	%

	Alliant Energy				IPL				WPL
Six Months Ended June 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	(11.9	)	(12.3	)	(32.8	)	(35.6	)	—		—
Production tax credits	(6.5	)	(7.7	)	(8.2	)	(10.1	)	(6.2	)	(7.0	)
Effect of rate-making on property-related differences	(5.1	)	(5.6	)	(13.0	)	(15.5	)	(0.7	)	(0.4	)
Other items, net	4.7		3.6		4.6		1.9		4.9		4.9
Overall income tax rate	16.2	%	13.0	%	(14.4	%)	(24.3	%)	33.0	%	32.5	%

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 IPL’s tax benefit riders. Refer to Note 2 for additional details of the tax benefit riders.

Production tax credits - For the three and six months ended June 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				Six Months
	Tax Credit Generation	Capacity in MW	2014		2013		2014		2013
Cedar Ridge (WPL)	December 2018	68		$1.0		$1.1		$2.2		$2.3
Bent Tree - Phase I (WPL)	February 2021	201	3.2		3.5		7.4		7.0
Subtotal (WPL)			4.2		4.6		9.6		9.3
Whispering Willow - East (IPL)	December 2019	200	3.2		4.1		7.8		8.0
				$7.4		$8.7		$17.4		$17.3

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.

Deferred Tax Assets and Liabilities - For the six months ended June 30, 2014, Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $77.2 million, $57.0 million and $21.1 million, respectively. These increases in non-current deferred tax liabilities were primarily due to property-related differences resulting from accelerated depreciation deductions, qualifying repairs expenditures, a tax accounting method change made for cost of removal expenditures and the effect of rate-making on property-related differences recorded during the six months ended June 30, 2014. Refer to Note 2 for further discussion of the tax accounting method change for cost of removal expenditures.

Carryforwards - At June 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		$721		$248	2029
State net operating losses	747		38		2018
Federal tax credits	188		185		2022
				$471

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$317		$109	2029
State net operating losses	222		11		2018
Federal tax credits	62		61		2022
				$181

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$308		$106	2029
State net operating losses	114		6		2018
Federal tax credits	68		67		2022
				$179

WPL [Member]

Income Taxes [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 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	Alliant Energy				IPL				WPL
Three Months Ended June 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	(11.9	)	(11.7	)	(36.6	)	(33.3	)	—		—
Production tax credits	(6.1	)	(7.9	)	(8.0	)	(10.5	)	(5.8	)	(7.2	)
Effect of rate-making on property-related differences	(4.8	)	(6.4	)	(14.4	)	(17.4	)	(0.2	)	(0.5	)
Other items, net	4.8		4.3		4.6		1.5		5.0		5.8
Overall income tax rate	17.0	%	13.3	%	(19.4	%)	(24.7	%)	34.0	%	33.1	%

	Alliant Energy				IPL				WPL
Six Months Ended June 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	(11.9	)	(12.3	)	(32.8	)	(35.6	)	—		—
Production tax credits	(6.5	)	(7.7	)	(8.2	)	(10.1	)	(6.2	)	(7.0	)
Effect of rate-making on property-related differences	(5.1	)	(5.6	)	(13.0	)	(15.5	)	(0.7	)	(0.4	)
Other items, net	4.7		3.6		4.6		1.9		4.9		4.9
Overall income tax rate	16.2	%	13.0	%	(14.4	%)	(24.3	%)	33.0	%	32.5	%

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 IPL’s tax benefit riders. Refer to Note 2 for additional details of the tax benefit riders.

Production tax credits - For the three and six months ended June 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				Six Months
	Tax Credit Generation	Capacity in MW	2014		2013		2014		2013
Cedar Ridge (WPL)	December 2018	68		$1.0		$1.1		$2.2		$2.3
Bent Tree - Phase I (WPL)	February 2021	201	3.2		3.5		7.4		7.0
Subtotal (WPL)			4.2		4.6		9.6		9.3
Whispering Willow - East (IPL)	December 2019	200	3.2		4.1		7.8		8.0
				$7.4		$8.7		$17.4		$17.3

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.

Deferred Tax Assets and Liabilities - For the six months ended June 30, 2014, Alliant Energy’s, IPL’s and WPL’s non-current deferred tax liabilities increased $77.2 million, $57.0 million and $21.1 million, respectively. These increases in non-current deferred tax liabilities were primarily due to property-related differences resulting from accelerated depreciation deductions, qualifying repairs expenditures, a tax accounting method change made for cost of removal expenditures and the effect of rate-making on property-related differences recorded during the six months ended June 30, 2014. Refer to Note 2 for further discussion of the tax accounting method change for cost of removal expenditures.

Carryforwards - At June 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		$721		$248	2029
State net operating losses	747		38		2018
Federal tax credits	188		185		2022
				$471

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$317		$109	2029
State net operating losses	222		11		2018
Federal tax credits	62		61		2022
				$181

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$308		$106	2029
State net operating losses	114		6		2018
Federal tax credits	68		67		2022
				$179