XML 54 R26.htm IDEA: XBRL DOCUMENT v2.4.0.8

Income Taxes (Tables)

6 Months Ended

Jun. 30, 2013

Income Tax [Line Items]

Schedule Of Effective Income Tax Rates

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
	2013			2012			2013			2012
Alliant Energy	13.3	%		19.5	%		13.0	%		28.3	%
IPL	(24.7	%)		(12.0	%)		(24.3	%)		22.6	%
WPL	33.1	%		34.6	%		32.5	%		39.4	%

IPL's Tax Benefit Riders

The tax impacts of the tax benefit riders decreased Alliant Energy’s and IPL’s effective income tax rates for continuing operations for the three and six months ended June 30 as follows. Refer to Note 1(b) for additional details of IPL’s tax benefit riders.

	Three Months						Six Months
	2013			2012			2013			2012
Alliant Energy	(11.7	%)		(11.7	%)		(12.3	%)		(11.9	%)
IPL	(33.3	%)		(34.9	%)		(35.6	%)		(35.5	%)

Production Tax Credits (Net Of State Tax Impacts)

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
	2013				2012				2013				2012
Cedar Ridge (WPL)		$1.1				$1.0				$2.3				$2.3
Bent Tree - Phase I (WPL)	3.5				2.7				7.0				4.2
Subtotal (WPL)	4.6				3.7				9.3				6.5
Whispering Willow - East (IPL)	4.1				3.1				8.0				6.7
		$8.7				$6.8				$17.3				$13.2

Schedule Of Effective Income Tax Rates (Production Tax Credits)

The tax impacts of the production tax credits decreased Alliant Energy’s, IPL’s and WPL’s effective income tax rates for continuing operations for the three and six months ended June 30 as follows:

	Three Months						Six Months
	2013			2012			2013			2012
Alliant Energy	(7.9	%)		(6.3	%)		(7.7	%)		(6.6	%)
IPL	(10.5	%)		(8.6	%)		(10.1	%)		(8.9	%)
WPL	(7.2	%)		(6.5	%)		(7.0	%)		(6.4	%)

Effect of Rate-making on Property-related Differences

The tax impacts of the effect of rate-making on property-related differences decreased Alliant Energy’s and IPL’s effective income tax rates for continuing operations for the three and six months ended June 30 as follows. 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 six months ended June 30, 2013 was repair expenditures at IPL.

	Three Months						Six Months
	2013			2012			2013			2012
Alliant Energy	(6.4	%)		(4.0	%)		(5.6	%)		(3.6	%)
IPL	(17.4	%)		(8.1	%)		(15.5	%)		(7.7	%)

Summary Of Tax Credit Carryforwards

At June 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		$841				$289			2029
State net operating losses	795				42				2018
Federal tax credits	155				153				2022
						$484

IPL	Carryforward Amount				Deferred Tax Assets				Earliest Expiration Date
Federal net operating losses		$385				$132			2029
State net operating losses	228				13				2018
Federal tax credits	47				46				2022
						$191

WPL	Carryforward Amount				Deferred Tax Assets				Earliest Expiration Date
Federal net operating losses		$342				$117			2029
State net operating losses	147				7				2018
Federal tax credits	50				49				2022
						$173

IPL [Member]

Income Tax [Line Items]

Schedule Of Effective Income Tax Rates

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
	2013			2012			2013			2012
Alliant Energy	13.3	%		19.5	%		13.0	%		28.3	%
IPL	(24.7	%)		(12.0	%)		(24.3	%)		22.6	%
WPL	33.1	%		34.6	%		32.5	%		39.4	%

IPL's Tax Benefit Riders

The tax impacts of the tax benefit riders decreased Alliant Energy’s and IPL’s effective income tax rates for continuing operations for the three and six months ended June 30 as follows. Refer to Note 1(b) for additional details of IPL’s tax benefit riders.

	Three Months						Six Months
	2013			2012			2013			2012
Alliant Energy	(11.7	%)		(11.7	%)		(12.3	%)		(11.9	%)
IPL	(33.3	%)		(34.9	%)		(35.6	%)		(35.5	%)

Production Tax Credits (Net Of State Tax Impacts)

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
	2013				2012				2013				2012
Cedar Ridge (WPL)		$1.1				$1.0				$2.3				$2.3
Bent Tree - Phase I (WPL)	3.5				2.7				7.0				4.2
Subtotal (WPL)	4.6				3.7				9.3				6.5
Whispering Willow - East (IPL)	4.1				3.1				8.0				6.7
		$8.7				$6.8				$17.3				$13.2

Schedule Of Effective Income Tax Rates (Production Tax Credits)

The tax impacts of the production tax credits decreased Alliant Energy’s, IPL’s and WPL’s effective income tax rates for continuing operations for the three and six months ended June 30 as follows:

	Three Months						Six Months
	2013			2012			2013			2012
Alliant Energy	(7.9	%)		(6.3	%)		(7.7	%)		(6.6	%)
IPL	(10.5	%)		(8.6	%)		(10.1	%)		(8.9	%)
WPL	(7.2	%)		(6.5	%)		(7.0	%)		(6.4	%)

Effect of Rate-making on Property-related Differences

The tax impacts of the effect of rate-making on property-related differences decreased Alliant Energy’s and IPL’s effective income tax rates for continuing operations for the three and six months ended June 30 as follows. 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 six months ended June 30, 2013 was repair expenditures at IPL.

	Three Months						Six Months
	2013			2012			2013			2012
Alliant Energy	(6.4	%)		(4.0	%)		(5.6	%)		(3.6	%)
IPL	(17.4	%)		(8.1	%)		(15.5	%)		(7.7	%)

Summary Of Tax Credit Carryforwards

At June 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		$841				$289			2029
State net operating losses	795				42				2018
Federal tax credits	155				153				2022
						$484

IPL	Carryforward Amount				Deferred Tax Assets				Earliest Expiration Date
Federal net operating losses		$385				$132			2029
State net operating losses	228				13				2018
Federal tax credits	47				46				2022
						$191

WPL	Carryforward Amount				Deferred Tax Assets				Earliest Expiration Date
Federal net operating losses		$342				$117			2029
State net operating losses	147				7				2018
Federal tax credits	50				49				2022
						$173

WPL [Member]

Income Tax [Line Items]

Schedule Of Effective Income Tax Rates

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
	2013			2012			2013			2012
Alliant Energy	13.3	%		19.5	%		13.0	%		28.3	%
IPL	(24.7	%)		(12.0	%)		(24.3	%)		22.6	%
WPL	33.1	%		34.6	%		32.5	%		39.4	%

Production Tax Credits (Net Of State Tax Impacts)

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
	2013				2012				2013				2012
Cedar Ridge (WPL)		$1.1				$1.0				$2.3				$2.3
Bent Tree - Phase I (WPL)	3.5				2.7				7.0				4.2
Subtotal (WPL)	4.6				3.7				9.3				6.5
Whispering Willow - East (IPL)	4.1				3.1				8.0				6.7
		$8.7				$6.8				$17.3				$13.2

Schedule Of Effective Income Tax Rates (Production Tax Credits)

The tax impacts of the production tax credits decreased Alliant Energy’s, IPL’s and WPL’s effective income tax rates for continuing operations for the three and six months ended June 30 as follows:

	Three Months						Six Months
	2013			2012			2013			2012
Alliant Energy	(7.9	%)		(6.3	%)		(7.7	%)		(6.6	%)
IPL	(10.5	%)		(8.6	%)		(10.1	%)		(8.9	%)
WPL	(7.2	%)		(6.5	%)		(7.0	%)		(6.4	%)

Summary Of Tax Credit Carryforwards

At June 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		$841				$289			2029
State net operating losses	795				42				2018
Federal tax credits	155				153				2022
						$484

IPL	Carryforward Amount				Deferred Tax Assets				Earliest Expiration Date
Federal net operating losses		$385				$132			2029
State net operating losses	228				13				2018
Federal tax credits	47				46				2022
						$191

WPL	Carryforward Amount				Deferred Tax Assets				Earliest Expiration Date
Federal net operating losses		$342				$117			2029
State net operating losses	147				7				2018
Federal tax credits	50				49				2022
						$173

X

- Definition

[Table Text Block] for Effect of Rate-making on Property-related Differences [Table]

+ References

No definition available.

+ Details

Name:	lnt_EffectOfRateMakingOnPropertyRelatedDifferencesTableTextBlock
Namespace Prefix:	lnt_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	lnt_IncomeTaxLineItems
Namespace Prefix:	lnt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

[Table Text Block] for IPL's Tax Benefit Riders [Table]

+ References

No definition available.

+ Details

Name:	lnt_IplsTaxBenefitRidersTableTextBlock
Namespace Prefix:	lnt_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Production Tax Credits Net of State Tax Impacts [Table Text Block]

+ References

No definition available.

+ Details

Name:	lnt_ProductionTaxCreditsNetOfStateTaxImpactsTableTextBlock
Namespace Prefix:	lnt_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Schedule Of Effective Income Tax Rates Production Tax Credits [Table Text Block]

+ References

No definition available.

+ Details

Name:	lnt_ScheduleOfEffectiveIncomeTaxRatesProductionTaxCreditsTableTextBlock
Namespace Prefix:	lnt_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- 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

Name:	us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of tax credit carryforwards available to reduce future taxable income, including amounts, expiration dates, limitations on use and the related deferred tax assets and valuation allowances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 43

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Carryforwards

-URI http://asc.fasb.org/extlink&oid=6506874



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 48

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 17

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_SummaryOfTaxCreditCarryforwardsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration