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Income Taxes (Tables)
 3 Months Ended
Mar. 31, 2024
Income Taxes [Line Items]  
Schedule Of Effective Income Tax Rates Overall effective income tax rates for the three months ended March 31, which were computed by dividing income tax expense (benefit) 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.
Alliant EnergyIPLWPL
202420232024202320242023
Overall income tax rate(7%)(1%)(19%)(18%)6%12%
Summary Of Tax Credit Carryforwards At March 31, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
Range of Expiration DatesAlliant EnergyIPLWPL
State net operating losses2025-2044$403$6$1
Federal tax credits2032-2044685462214
IPL [Member]  
Income Taxes [Line Items]  
Schedule Of Effective Income Tax Rates Overall effective income tax rates for the three months ended March 31, which were computed by dividing income tax expense (benefit) 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.
Alliant EnergyIPLWPL
202420232024202320242023
Overall income tax rate(7%)(1%)(19%)(18%)6%12%
Summary Of Tax Credit Carryforwards At March 31, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
Range of Expiration DatesAlliant EnergyIPLWPL
State net operating losses2025-2044$403$6$1
Federal tax credits2032-2044685462214
WPL [Member]  
Income Taxes [Line Items]  
Schedule Of Effective Income Tax Rates Overall effective income tax rates for the three months ended March 31, which were computed by dividing income tax expense (benefit) 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.
Alliant EnergyIPLWPL
202420232024202320242023
Overall income tax rate(7%)(1%)(19%)(18%)6%12%
Summary Of Tax Credit Carryforwards At March 31, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
Range of Expiration DatesAlliant EnergyIPLWPL
State net operating losses2025-2044$403$6$1
Federal tax credits2032-2044685462214