INCOME TAXES

Income Tax Rates - Overall effective income tax rates, which were computed by dividing income taxes by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The decreases in overall effective income tax rates for the three months ended March 31, 2020 compared to the same period in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.



	Alliant Energy				IPL				WPL
Three Months Ended March 31	2020		2019		2020		2019		2020		2019
Overall income tax rate	(12.2	%)	10.6	%	(19.8	%)	3.6	%	(10.1	%)	18.2	%

Deferred Tax Assets and Liabilities -

Carryforwards - At March 31, 2020, carryforwards and expiration dates were estimated as follows (in millions):



	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$280		$260		$2
State net operating losses	2020-2040	606		12		2
Federal tax credits	2022-2040	386		199		167

Income Taxes [Line Items]

Income Taxes

INCOME TAXES

Income Tax Rates - Overall effective income tax rates, which were computed by dividing income taxes by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The decreases in overall effective income tax rates for the three months ended March 31, 2020 compared to the same period in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.



	Alliant Energy				IPL				WPL
Three Months Ended March 31	2020		2019		2020		2019		2020		2019
Overall income tax rate	(12.2	%)	10.6	%	(19.8	%)	3.6	%	(10.1	%)	18.2	%

Deferred Tax Assets and Liabilities -

Carryforwards - At March 31, 2020, carryforwards and expiration dates were estimated as follows (in millions):



	Range of Expiration Dates	Alliant Energy		IPL		WPL
Federal net operating losses	2037		$280		$260		$2
State net operating losses	2020-2040	606		12		2
Federal tax credits	2022-2040	386		199		167