Income Taxes (Tables)

3 Months Ended

Mar. 31, 2013

Income Tax [Line Items]

Schedule Of Effective Income Tax Rates

The effective income tax rates shown in the following table for the three months ended March 31 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	2013		2012
Alliant Energy	12.7	%	39.0	%
IPL	(24.0	%)	125.4	%
WPL	32.0	%	44.1	%

Production Tax Credits (Net Of State Tax Impacts)

For the three months ended March 31, production tax credits (net of state tax impacts) resulting from these wind projects were as follows (in millions):

	2013		2012
Cedar Ridge (WPL)		$1.2		$1.3
Bent Tree - Phase I (WPL)	3.5		1.5
Subtotal (WPL)	4.7		2.8
Whispering Willow - East (IPL)	3.9		3.6
		$8.6		$6.4

Summary Of Tax Credit Carryforwards

At March 31, 2013, 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		$863		$296	2029
State net operating losses	808		43		2019
Federal tax credits	146		144		2022
				$483

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$400		$137	2029
State net operating losses	238		14		2018
Federal tax credits	43		42		2022
				$193

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$349		$120	2029
State net operating losses	148		7		2018
Federal tax credits	46		45		2022
				$172

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 months ended March 31 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	2013		2012
Alliant Energy	12.7	%	39.0	%
IPL	(24.0	%)	125.4	%
WPL	32.0	%	44.1	%

Production Tax Credits (Net Of State Tax Impacts)

For the three months ended March 31, production tax credits (net of state tax impacts) resulting from these wind projects were as follows (in millions):

	2013		2012
Cedar Ridge (WPL)		$1.2		$1.3
Bent Tree - Phase I (WPL)	3.5		1.5
Subtotal (WPL)	4.7		2.8
Whispering Willow - East (IPL)	3.9		3.6
		$8.6		$6.4

Summary Of Tax Credit Carryforwards

At March 31, 2013, 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		$863		$296	2029
State net operating losses	808		43		2019
Federal tax credits	146		144		2022
				$483

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$400		$137	2029
State net operating losses	238		14		2018
Federal tax credits	43		42		2022
				$193

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$349		$120	2029
State net operating losses	148		7		2018
Federal tax credits	46		45		2022
				$172

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 months ended March 31 were computed by dividing income tax expense (benefit) by income from continuing operations before income taxes.

	2013		2012
Alliant Energy	12.7	%	39.0	%
IPL	(24.0	%)	125.4	%
WPL	32.0	%	44.1	%

Production Tax Credits (Net Of State Tax Impacts)

For the three months ended March 31, production tax credits (net of state tax impacts) resulting from these wind projects were as follows (in millions):

	2013		2012
Cedar Ridge (WPL)		$1.2		$1.3
Bent Tree - Phase I (WPL)	3.5		1.5
Subtotal (WPL)	4.7		2.8
Whispering Willow - East (IPL)	3.9		3.6
		$8.6		$6.4

Summary Of Tax Credit Carryforwards

At March 31, 2013, 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		$863		$296	2029
State net operating losses	808		43		2019
Federal tax credits	146		144		2022
				$483

IPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$400		$137	2029
State net operating losses	238		14		2018
Federal tax credits	43		42		2022
				$193

WPL	Carryforward Amount		Deferred Tax Assets		Earliest Expiration Date
Federal net operating losses		$349		$120	2029
State net operating losses	148		7		2018
Federal tax credits	46		45		2022
				$172