アライアントエナジーの年次報告

00003525412023FYfalse00000524850000107832http://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrenthttp://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#PropertyPlantAndEquipmentNethttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesCurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrenthttp://fasb.org/us-gaap/2023#OtherLiabilitiesNoncurrent00003525412023-01-012023-12-310000352541lnt:IplMember2023-01-012023-12-310000352541lnt:WplMember2023-01-012023-12-3100003525412023-06-30iso4217:USD0000352541lnt:IplMember2023-06-300000352541lnt:WplMember2023-06-3000003525412024-01-31xbrli:shares0000352541lnt:IplMember2024-01-310000352541lnt:WplMember2024-01-3100003525412022-01-012022-12-3100003525412021-01-012021-12-310000352541us-gaap:OtherCustomerMemberus-gaap:AllOtherSegmentsMember2023-01-012023-12-31iso4217:USDxbrli:shares00003525412023-12-3100003525412022-12-3100003525412021-12-3100003525412020-12-310000352541lnt:RenewableTaxCreditsTransferredMemberus-gaap:IndemnificationGuaranteeMember2023-01-012023-12-310000352541us-gaap:CommonStockMember2020-12-310000352541us-gaap:AdditionalPaidInCapitalMember2020-12-310000352541us-gaap:RetainedEarningsMember2020-12-310000352541us-gaap:AccumulatedOtherComprehensiveIncomeMember2020-12-310000352541us-gaap:DeferredCompensationShareBasedPaymentsMember2020-12-310000352541us-gaap:PreferredStockMember2020-12-310000352541us-gaap:RetainedEarningsMember2021-01-012021-12-310000352541us-gaap:CommonStockMember2021-01-012021-12-310000352541us-gaap:AdditionalPaidInCapitalMember2021-01-012021-12-310000352541us-gaap:DeferredCompensationShareBasedPaymentsMember2021-01-012021-12-310000352541us-gaap:PreferredStockMember2021-01-012021-12-310000352541us-gaap:AccumulatedOtherComprehensiveIncomeMember2021-01-012021-12-310000352541us-gaap:CommonStockMember2021-12-310000352541us-gaap:AdditionalPaidInCapitalMember2021-12-310000352541us-gaap:RetainedEarningsMember2021-12-310000352541us-gaap:AccumulatedOtherComprehensiveIncomeMember2021-12-310000352541us-gaap:DeferredCompensationShareBasedPaymentsMember2021-12-310000352541us-gaap:PreferredStockMember2021-12-310000352541us-gaap:RetainedEarningsMember2022-01-012022-12-310000352541us-gaap:AdditionalPaidInCapitalMember2022-01-012022-12-310000352541us-gaap:DeferredCompensationShareBasedPaymentsMember2022-01-012022-12-310000352541us-gaap:CommonStockMember2022-12-310000352541us-gaap:AdditionalPaidInCapitalMember2022-12-310000352541us-gaap:RetainedEarningsMember2022-12-310000352541us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-12-310000352541us-gaap:DeferredCompensationShareBasedPaymentsMember2022-12-310000352541us-gaap:PreferredStockMember2022-12-310000352541us-gaap:RetainedEarningsMember2023-01-012023-12-310000352541us-gaap:AdditionalPaidInCapitalMember2023-01-012023-12-310000352541us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-01-012023-12-310000352541us-gaap:CommonStockMember2023-12-310000352541us-gaap:AdditionalPaidInCapitalMember2023-12-310000352541us-gaap:RetainedEarningsMember2023-12-310000352541us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-12-310000352541us-gaap:DeferredCompensationShareBasedPaymentsMember2023-12-310000352541us-gaap:PreferredStockMember2023-12-310000352541lnt:IplMember2022-01-012022-12-310000352541lnt:IplMember2021-01-012021-12-310000352541lnt:IplMember2023-12-310000352541lnt:IplMember2022-12-310000352541lnt:IplMember2021-12-310000352541lnt:IplMember2020-12-310000352541lnt:RenewableTaxCreditsTransferredMemberus-gaap:IndemnificationGuaranteeMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:CommonStockMemberlnt:IplMember2020-12-310000352541us-gaap:AdditionalPaidInCapitalMemberlnt:IplMember2020-12-310000352541us-gaap:RetainedEarningsMemberlnt:IplMember2020-12-310000352541us-gaap:PreferredStockMemberlnt:IplMember2020-12-310000352541us-gaap:RetainedEarningsMemberlnt:IplMember2021-01-012021-12-310000352541us-gaap:AdditionalPaidInCapitalMemberlnt:IplMember2021-01-012021-12-310000352541us-gaap:PreferredStockMemberlnt:IplMember2021-01-012021-12-310000352541us-gaap:CommonStockMemberlnt:IplMember2021-12-310000352541us-gaap:AdditionalPaidInCapitalMemberlnt:IplMember2021-12-310000352541us-gaap:RetainedEarningsMemberlnt:IplMember2021-12-310000352541us-gaap:PreferredStockMemberlnt:IplMember2021-12-310000352541us-gaap:RetainedEarningsMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:CommonStockMemberlnt:IplMember2022-12-310000352541us-gaap:AdditionalPaidInCapitalMemberlnt:IplMember2022-12-310000352541us-gaap:RetainedEarningsMemberlnt:IplMember2022-12-310000352541us-gaap:PreferredStockMemberlnt:IplMember2022-12-310000352541us-gaap:RetainedEarningsMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:AdditionalPaidInCapitalMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:CommonStockMemberlnt:IplMember2023-12-310000352541us-gaap:AdditionalPaidInCapitalMemberlnt:IplMember2023-12-310000352541us-gaap:RetainedEarningsMemberlnt:IplMember2023-12-310000352541us-gaap:PreferredStockMemberlnt:IplMember2023-12-310000352541lnt:WplMember2022-01-012022-12-310000352541lnt:WplMember2021-01-012021-12-310000352541lnt:WplMember2023-12-310000352541lnt:WplMember2022-12-310000352541lnt:WplMember2021-12-310000352541lnt:WplMember2020-12-310000352541lnt:WplMemberlnt:RenewableTaxCreditsTransferredMemberus-gaap:IndemnificationGuaranteeMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:CommonStockMember2020-12-310000352541lnt:WplMemberus-gaap:AdditionalPaidInCapitalMember2020-12-310000352541lnt:WplMemberus-gaap:RetainedEarningsMember2020-12-310000352541lnt:WplMemberus-gaap:RetainedEarningsMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:AdditionalPaidInCapitalMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:CommonStockMember2021-12-310000352541lnt:WplMemberus-gaap:AdditionalPaidInCapitalMember2021-12-310000352541lnt:WplMemberus-gaap:RetainedEarningsMember2021-12-310000352541lnt:WplMemberus-gaap:RetainedEarningsMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:AdditionalPaidInCapitalMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:CommonStockMember2022-12-310000352541lnt:WplMemberus-gaap:AdditionalPaidInCapitalMember2022-12-310000352541lnt:WplMemberus-gaap:RetainedEarningsMember2022-12-310000352541lnt:WplMemberus-gaap:RetainedEarningsMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:AdditionalPaidInCapitalMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:CommonStockMember2023-12-310000352541lnt:WplMemberus-gaap:AdditionalPaidInCapitalMember2023-12-310000352541lnt:WplMemberus-gaap:RetainedEarningsMember2023-12-31lnt:customer0000352541lnt:AlliantEnergyFinanceLLCMemberlnt:WindInvestmentinOklahomaMember2023-12-31xbrli:pure0000352541lnt:AlliantEnergyFinanceLLCMember2023-01-012023-12-31utr:MW0000352541lnt:SheboyganFallsEnergyFacilityMember2023-01-012023-12-310000352541us-gaap:ElectricGenerationEquipmentMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:ElectricGenerationEquipmentMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:ElectricGenerationEquipmentMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:ElectricGenerationEquipmentMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:ElectricGenerationEquipmentMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:ElectricGenerationEquipmentMember2021-01-012021-12-310000352541us-gaap:ElectricDistributionMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:ElectricDistributionMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:ElectricDistributionMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:ElectricDistributionMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:ElectricDistributionMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:ElectricDistributionMember2021-01-012021-12-310000352541us-gaap:OtherEnergyEquipmentMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:OtherEnergyEquipmentMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:OtherEnergyEquipmentMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:OtherEnergyEquipmentMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:OtherEnergyEquipmentMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:OtherEnergyEquipmentMember2021-01-012021-12-310000352541lnt:IplMemberus-gaap:GasTransmissionMember2023-01-012023-12-310000352541lnt:IplMemberus-gaap:GasTransmissionMember2022-01-012022-12-310000352541lnt:IplMemberus-gaap:GasTransmissionMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:GasTransmissionMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:GasTransmissionMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:GasTransmissionMember2021-01-012021-12-310000352541lnt:IplMemberus-gaap:OtherPlantInServiceMember2023-01-012023-12-310000352541lnt:IplMemberus-gaap:OtherPlantInServiceMember2022-01-012022-12-310000352541lnt:IplMemberus-gaap:OtherPlantInServiceMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:OtherPlantInServiceMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:OtherPlantInServiceMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:OtherPlantInServiceMember2021-01-012021-12-310000352541lnt:IplMemberlnt:IPLfercformulawindgenerationMember2023-01-012023-12-310000352541lnt:IplMemberlnt:IPLfercformulawindgenerationMember2022-01-012022-12-310000352541lnt:IplMemberlnt:IPLfercformulawindgenerationMember2021-01-012021-12-310000352541lnt:IplFercFormulaOtherProjectsMemberlnt:IplMember2023-01-012023-12-310000352541lnt:IplFercFormulaOtherProjectsMemberlnt:IplMember2022-01-012022-12-310000352541lnt:IplFercFormulaOtherProjectsMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberlnt:WplPscwFormulaRetailJurisdictionMember2023-01-012023-12-310000352541lnt:WplMemberlnt:WplPscwFormulaRetailJurisdictionMember2022-01-012022-12-310000352541lnt:WplMemberlnt:WplPscwFormulaRetailJurisdictionMember2021-01-012021-12-310000352541lnt:WplMemberlnt:WplFercFormulaWholesaleJurisdictionMember2023-01-012023-12-310000352541lnt:WplMemberlnt:WplFercFormulaWholesaleJurisdictionMember2022-01-012022-12-310000352541lnt:WplMemberlnt:WplFercFormulaWholesaleJurisdictionMember2021-01-012021-12-310000352541us-gaap:DeferredIncomeTaxChargesMember2023-12-310000352541us-gaap:DeferredIncomeTaxChargesMember2022-12-310000352541us-gaap:DeferredIncomeTaxChargesMemberlnt:IplMember2023-12-310000352541us-gaap:DeferredIncomeTaxChargesMemberlnt:IplMember2022-12-310000352541us-gaap:DeferredIncomeTaxChargesMemberlnt:WplMember2023-12-310000352541us-gaap:DeferredIncomeTaxChargesMemberlnt:WplMember2022-12-310000352541lnt:PensionAndOtherPostretirementBenefitsMember2023-12-310000352541lnt:PensionAndOtherPostretirementBenefitsMember2022-12-310000352541lnt:IplMemberlnt:PensionAndOtherPostretirementBenefitsMember2023-12-310000352541lnt:IplMemberlnt:PensionAndOtherPostretirementBenefitsMember2022-12-310000352541lnt:WplMemberlnt:PensionAndOtherPostretirementBenefitsMember2023-12-310000352541lnt:WplMemberlnt:PensionAndOtherPostretirementBenefitsMember2022-12-310000352541lnt:ElectricGeneratingUnitsRetiredEarlyMemberMember2023-12-310000352541lnt:ElectricGeneratingUnitsRetiredEarlyMemberMember2022-12-310000352541lnt:ElectricGeneratingUnitsRetiredEarlyMemberMemberlnt:IplMember2023-12-310000352541lnt:ElectricGeneratingUnitsRetiredEarlyMemberMemberlnt:IplMember2022-12-310000352541lnt:WplMemberlnt:ElectricGeneratingUnitsRetiredEarlyMemberMember2023-12-310000352541lnt:WplMemberlnt:ElectricGeneratingUnitsRetiredEarlyMemberMember2022-12-310000352541us-gaap:AssetRetirementObligationCostsMember2023-12-310000352541us-gaap:AssetRetirementObligationCostsMember2022-12-310000352541lnt:IplMemberus-gaap:AssetRetirementObligationCostsMember2023-12-310000352541lnt:IplMemberus-gaap:AssetRetirementObligationCostsMember2022-12-310000352541lnt:WplMemberus-gaap:AssetRetirementObligationCostsMember2023-12-310000352541lnt:WplMemberus-gaap:AssetRetirementObligationCostsMember2022-12-310000352541lnt:CommodityCostRecoveryMember2023-12-310000352541lnt:CommodityCostRecoveryMember2022-12-310000352541lnt:IplMemberlnt:CommodityCostRecoveryMember2023-12-310000352541lnt:IplMemberlnt:CommodityCostRecoveryMember2022-12-310000352541lnt:WplMemberlnt:CommodityCostRecoveryMember2023-12-310000352541lnt:WplMemberlnt:CommodityCostRecoveryMember2022-12-310000352541us-gaap:DeferredDerivativeGainLossMember2023-12-310000352541us-gaap:DeferredDerivativeGainLossMember2022-12-310000352541us-gaap:DeferredDerivativeGainLossMemberlnt:IplMember2023-12-310000352541us-gaap:DeferredDerivativeGainLossMemberlnt:IplMember2022-12-310000352541lnt:WplMemberus-gaap:DeferredDerivativeGainLossMember2023-12-310000352541lnt:WplMemberus-gaap:DeferredDerivativeGainLossMember2022-12-310000352541lnt:WesternWisconsinGasDistributionExpansionInvestmentsMember2023-12-310000352541lnt:WesternWisconsinGasDistributionExpansionInvestmentsMember2022-12-310000352541lnt:WplMemberlnt:WesternWisconsinGasDistributionExpansionInvestmentsMember2023-12-310000352541lnt:WplMemberlnt:WesternWisconsinGasDistributionExpansionInvestmentsMember2022-12-310000352541lnt:DAECPPAMember2023-12-310000352541lnt:DAECPPAMember2022-12-310000352541lnt:IplMemberlnt:DAECPPAMember2023-12-310000352541lnt:IplMemberlnt:DAECPPAMember2022-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMember2023-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMember2022-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMemberlnt:IplMember2023-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMemberlnt:IplMember2022-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMemberlnt:WplMember2023-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMemberlnt:WplMember2022-12-310000352541lnt:LansingMemberlnt:ElectricGeneratingUnitsRetiredEarlyMemberMemberlnt:IplMember2023-12-310000352541lnt:ElectricGeneratingUnitsRetiredEarlyMemberMemberlnt:IplMemberlnt:AnalogElectricMetersMember2023-12-310000352541lnt:SutherlandUnitsOneAndThreeMemberlnt:ElectricGeneratingUnitsRetiredEarlyMemberMemberlnt:IplMember2023-12-310000352541lnt:MLKappMemberlnt:ElectricGeneratingUnitsRetiredEarlyMemberMemberlnt:IplMember2023-12-310000352541lnt:WplMemberlnt:EdgewaterUnit4Memberlnt:ElectricGeneratingUnitsRetiredEarlyMemberMember2023-12-310000352541lnt:WplMemberlnt:A2021TestPeriodFuelRelatedCostsMember2022-12-310000352541lnt:WplMemberlnt:A2022TestPeriodFuelRelatedCostsMember2022-12-310000352541lnt:WplMemberlnt:A2022TestPeriodFuelRelatedCostsMember2023-01-012023-12-310000352541lnt:WplMemberlnt:A2023TestPeriodFuelRelatedCostsMember2023-12-310000352541lnt:DAECPPAMember2020-01-012020-12-310000352541lnt:DAECPPAMember2023-01-012023-12-310000352541lnt:TaxRelatedMember2023-12-310000352541lnt:TaxRelatedMember2022-12-310000352541lnt:TaxRelatedMemberlnt:IplMember2023-12-310000352541lnt:TaxRelatedMemberlnt:IplMember2022-12-310000352541lnt:WplMemberlnt:TaxRelatedMember2023-12-310000352541lnt:WplMemberlnt:TaxRelatedMember2022-12-310000352541lnt:CostOfRemovalObligationsMember2023-12-310000352541lnt:CostOfRemovalObligationsMember2022-12-310000352541lnt:IplMemberlnt:CostOfRemovalObligationsMember2023-12-310000352541lnt:IplMemberlnt:CostOfRemovalObligationsMember2022-12-310000352541lnt:WplMemberlnt:CostOfRemovalObligationsMember2023-12-310000352541lnt:WplMemberlnt:CostOfRemovalObligationsMember2022-12-310000352541us-gaap:DeferredDerivativeGainLossMember2023-12-310000352541us-gaap:DeferredDerivativeGainLossMember2022-12-310000352541us-gaap:DeferredDerivativeGainLossMemberlnt:IplMember2023-12-310000352541us-gaap:DeferredDerivativeGainLossMemberlnt:IplMember2022-12-310000352541us-gaap:DeferredDerivativeGainLossMemberlnt:WplMember2023-12-310000352541us-gaap:DeferredDerivativeGainLossMemberlnt:WplMember2022-12-310000352541lnt:CommodityCostRecoveryMember2023-12-310000352541lnt:CommodityCostRecoveryMember2022-12-310000352541lnt:IplMemberlnt:CommodityCostRecoveryMember2023-12-310000352541lnt:IplMemberlnt:CommodityCostRecoveryMember2022-12-310000352541lnt:WplMemberlnt:CommodityCostRecoveryMember2023-12-310000352541lnt:WplMemberlnt:CommodityCostRecoveryMember2022-12-310000352541lnt:WestRiversideLiquidatedDamagesMember2023-12-310000352541lnt:WestRiversideLiquidatedDamagesMember2022-12-310000352541lnt:WplMemberlnt:WestRiversideLiquidatedDamagesMember2023-12-310000352541lnt:WplMemberlnt:WestRiversideLiquidatedDamagesMember2022-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMember2023-12-310000352541us-gaap:OtherRegulatoryAssetsLiabilitiesMember2022-12-310000352541lnt:IplMemberus-gaap:OtherRegulatoryAssetsLiabilitiesMember2023-12-310000352541lnt:IplMemberus-gaap:OtherRegulatoryAssetsLiabilitiesMember2022-12-310000352541lnt:WplMemberus-gaap:OtherRegulatoryAssetsLiabilitiesMember2023-12-310000352541lnt:WplMemberus-gaap:OtherRegulatoryAssetsLiabilitiesMember2022-12-310000352541lnt:WplMemberlnt:TwoThousandTwentyTwoTestPeriodRetailElectricMember2022-01-012022-12-310000352541lnt:TwoThousandTwentyTwoTestPeriodRetailGasMemberlnt:WplMember2022-01-012022-12-310000352541lnt:WplMemberlnt:TwoThousandTwentyThreeTestPeriodRetailGasMember2023-01-012023-12-310000352541lnt:WplMembersrt:ScenarioForecastMemberlnt:TwoThousandTwentyFourTestPeriodRetailElectricMember2024-01-012024-12-310000352541lnt:WplMembersrt:ScenarioForecastMemberlnt:TwoThousandTwentyFourTestPeriodRetailGasMember2024-01-012024-12-310000352541lnt:WplMembersrt:ScenarioForecastMemberlnt:TwoThousandTwentyFiveTestPeriodRetailElectricMember2025-01-012025-12-310000352541lnt:ElectricGenerationMember2023-12-310000352541lnt:ElectricGenerationMember2022-12-310000352541lnt:ElectricGenerationMemberlnt:IplMember2023-12-310000352541lnt:ElectricGenerationMemberlnt:IplMember2022-12-310000352541lnt:WplMemberlnt:ElectricGenerationMember2023-12-310000352541lnt:WplMemberlnt:ElectricGenerationMember2022-12-310000352541us-gaap:ElectricDistributionMember2023-12-310000352541us-gaap:ElectricDistributionMember2022-12-310000352541us-gaap:ElectricDistributionMemberlnt:IplMember2023-12-310000352541us-gaap:ElectricDistributionMemberlnt:IplMember2022-12-310000352541lnt:WplMemberus-gaap:ElectricDistributionMember2023-12-310000352541lnt:WplMemberus-gaap:ElectricDistributionMember2022-12-310000352541us-gaap:OtherPlantInServiceMember2023-12-310000352541us-gaap:OtherPlantInServiceMember2022-12-310000352541lnt:IplMemberus-gaap:OtherPlantInServiceMember2023-12-310000352541lnt:IplMemberus-gaap:OtherPlantInServiceMember2022-12-310000352541lnt:WplMemberus-gaap:OtherPlantInServiceMember2023-12-310000352541lnt:WplMemberus-gaap:OtherPlantInServiceMember2022-12-310000352541lnt:WplMemberlnt:EdgewaterUnit5Member2023-12-310000352541lnt:ColumbiaUnits1And2Memberlnt:WplMember2023-12-310000352541us-gaap:EquityMember2023-01-012023-12-310000352541us-gaap:EquityMember2022-01-012022-12-310000352541us-gaap:EquityMember2021-01-012021-12-310000352541us-gaap:EquityMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:EquityMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:EquityMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:EquityMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:EquityMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:EquityMember2021-01-012021-12-310000352541us-gaap:DebtMember2023-01-012023-12-310000352541us-gaap:DebtMember2022-01-012022-12-310000352541us-gaap:DebtMember2021-01-012021-12-310000352541us-gaap:DebtMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:DebtMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:DebtMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:DebtMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:DebtMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:DebtMember2021-01-012021-12-310000352541lnt:SheboyganFallsEnergyFacilityMember2023-12-310000352541lnt:CustomerBillingAndInformationSystemMember2023-12-310000352541us-gaap:SoftwareAndSoftwareDevelopmentCostsMember2023-12-310000352541srt:MinimumMemberlnt:CorporateServicesMember2023-12-310000352541srt:MaximumMemberlnt:CorporateServicesMember2023-12-310000352541lnt:IplMemberlnt:OttumwaUnit1Member2023-12-310000352541lnt:GeorgeNealUnit4Memberlnt:IplMember2023-12-310000352541lnt:IplMemberlnt:GeorgeNealUnit3Member2023-12-310000352541lnt:IplMemberlnt:LouisaUnit1Member2023-12-310000352541lnt:WplMemberlnt:ColumbiaUnits1And2Member2023-12-310000352541lnt:WplMemberlnt:RiversideEnergyCenterMember2023-12-310000352541lnt:WplMemberlnt:ForwardWindEnergyCenterMember2023-12-310000352541srt:MinimumMember2023-12-310000352541srt:MaximumMember2023-12-310000352541us-gaap:FinanceReceivablesMemberlnt:IplMember2023-12-310000352541srt:MaximumMemberlnt:IplMember2023-01-012023-12-310000352541srt:MaximumMemberlnt:IplMember2022-01-012022-12-310000352541srt:MaximumMemberlnt:IplMember2021-01-012021-12-310000352541lnt:IplMembersrt:WeightedAverageMember2023-01-012023-12-310000352541lnt:IplMembersrt:WeightedAverageMember2022-01-012022-12-310000352541lnt:IplMembersrt:WeightedAverageMember2021-01-012021-12-310000352541us-gaap:FinanceReceivablesMemberlnt:IplMember2022-12-310000352541us-gaap:SubsequentEventMembersrt:MaximumMember2024-12-310000352541lnt:AmericanTransmissionCompanyLlcAtcMember2023-12-310000352541lnt:ATCHoldcoLLCMember2023-12-310000352541lnt:InvestmentInAtcMember2023-12-310000352541lnt:InvestmentInAtcMember2022-12-310000352541lnt:InvestmentInAtcMember2023-01-012023-12-310000352541lnt:InvestmentInAtcMember2022-01-012022-12-310000352541lnt:InvestmentInAtcMember2021-01-012021-12-310000352541lnt:WindInvestmentinOklahomaMember2023-12-310000352541lnt:WindInvestmentinOklahomaMember2022-12-310000352541lnt:WindInvestmentinOklahomaMember2023-01-012023-12-310000352541lnt:WindInvestmentinOklahomaMember2022-01-012022-12-310000352541lnt:WindInvestmentinOklahomaMember2021-01-012021-12-310000352541lnt:CorporateVentureInvestmentsMember2023-12-310000352541lnt:CorporateVentureInvestmentsMember2022-12-310000352541lnt:CorporateVentureInvestmentsMember2023-01-012023-12-310000352541lnt:CorporateVentureInvestmentsMember2022-01-012022-12-310000352541lnt:CorporateVentureInvestmentsMember2021-01-012021-12-310000352541lnt:OtherEquityMethodInvestmentsMember2023-12-310000352541lnt:OtherEquityMethodInvestmentsMember2022-12-310000352541lnt:OtherEquityMethodInvestmentsMember2023-01-012023-12-310000352541lnt:OtherEquityMethodInvestmentsMember2022-01-012022-12-310000352541lnt:OtherEquityMethodInvestmentsMember2021-01-012021-12-310000352541lnt:TotalsMember2023-12-310000352541lnt:TotalsMember2022-12-310000352541lnt:TotalsMember2023-01-012023-12-310000352541lnt:TotalsMember2022-01-012022-12-310000352541lnt:TotalsMember2021-01-012021-12-310000352541us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember2023-01-012023-12-310000352541us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember2022-01-012022-12-310000352541us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember2021-01-012021-12-310000352541us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember2023-12-310000352541us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember2022-12-310000352541lnt:AtTheMarketOfferingProgramMember2023-01-012023-12-310000352541lnt:AtTheMarketOfferingProgramMember2022-01-012022-12-310000352541lnt:AtTheMarketOfferingProgramMember2021-01-012021-12-310000352541lnt:IplMemberus-gaap:RedeemablePreferredStockMember2020-12-310000352541lnt:IplMemberus-gaap:RedeemablePreferredStockMember2020-01-012020-12-310000352541lnt:IplMemberus-gaap:RedeemablePreferredStockMember2021-01-012021-12-310000352541srt:ParentCompanyMember2023-12-310000352541srt:ScenarioForecastMembersrt:ParentCompanyMember2024-12-310000352541srt:ScenarioForecastMemberlnt:IplMember2024-12-310000352541lnt:WplMembersrt:ScenarioForecastMember2024-12-310000352541us-gaap:SubsequentEventMember2024-12-310000352541us-gaap:SubsequentEventMemberlnt:IplMember2024-12-310000352541lnt:WplMemberus-gaap:SubsequentEventMember2024-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointTwoFivePercentSeniorDebenturesDueTwoThousandTwentyFourMemberDomain2023-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointTwoFivePercentSeniorDebenturesDueTwoThousandTwentyFourMemberDomainlnt:IplMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointTwoFivePercentSeniorDebenturesDueTwoThousandTwentyFourMemberDomain2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointTwoFivePercentSeniorDebenturesDueTwoThousandTwentyFourMemberDomainlnt:IplMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointFourPercentSeniorDebenturesDueTwoThousandTwentyFiveMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointFourPercentSeniorDebenturesDueTwoThousandTwentyFiveMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointFourPercentSeniorDebenturesDueTwoThousandTwentyFiveMemberlnt:IplMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointFourPercentSeniorDebenturesDueTwoThousandTwentyFiveMemberlnt:IplMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:FivePointFivePercentSeniorDebenturesDueTwoThousandTwentyFiveMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:FivePointFivePercentSeniorDebenturesDueTwoThousandTwentyFiveMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:FivePointFivePercentSeniorDebenturesDueTwoThousandTwentyFiveMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:FivePointFivePercentSeniorDebenturesDueTwoThousandTwentyFiveMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:FourPointOneSeniorDebenturesDueTwoThousandTwentyEightMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:FourPointOneSeniorDebenturesDueTwoThousandTwentyEightMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:FourPointOneSeniorDebenturesDueTwoThousandTwentyEightMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:FourPointOneSeniorDebenturesDueTwoThousandTwentyEightMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointSixPercentSeniorDebenturesDueTwoThousandTwentyNineMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:ThreePointSixPercentSeniorDebenturesDueTwoThousandTwentyNineMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointSixPercentSeniorDebenturesDueTwoThousandTwentyNineMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:ThreePointSixPercentSeniorDebenturesDueTwoThousandTwentyNineMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:TwoPointThreePercentSeniorDebenturesDueTwoThousandThirtyMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:TwoPointThreePercentSeniorDebenturesDueTwoThousandThirtyMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:TwoPointThreePercentSeniorDebenturesDueTwoThousandThirtyMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:TwoPointThreePercentSeniorDebenturesDueTwoThousandThirtyMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:FivePointSevenPercentSeniorDebenturesDueTwoThousandThirtyThreeMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:FivePointSevenPercentSeniorDebenturesDueTwoThousandThirtyThreeMemberlnt:IplMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:FivePointSevenPercentSeniorDebenturesDueTwoThousandThirtyThreeMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:FivePointSevenPercentSeniorDebenturesDueTwoThousandThirtyThreeMemberlnt:IplMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointFourFivePercentSeniorDebenturesDueTwoThousandThirtyThreeMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:SixPointFourFivePercentSeniorDebenturesDueTwoThousandThirtyThreeMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointFourFivePercentSeniorDebenturesDueTwoThousandThirtyThreeMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:SixPointFourFivePercentSeniorDebenturesDueTwoThousandThirtyThreeMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointThreePercentSeniorDebenturesDueTwoThousandThirtyFourMemberlnt:IplMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointThreePercentSeniorDebenturesDueTwoThousandThirtyFourMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointThreePercentSeniorDebenturesDueTwoThousandThirtyFourMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointThreePercentSeniorDebenturesDueTwoThousandThirtyFourMemberlnt:IplMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:SixPointTwoFivePercentSeniorDebenturesDueTwoThousandThirtyNineMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:SixPointTwoFivePercentSeniorDebenturesDueTwoThousandThirtyNineMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointTwoFivePercentSeniorDebenturesDueTwoThousandThirtyNineMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:SixPointTwoFivePercentSeniorDebenturesDueTwoThousandThirtyNineMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:FourPointSevenPercentSeniorDebenturesDueTwoThousandFortyThreeMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:FourPointSevenPercentSeniorDebenturesDueTwoThousandFortyThreeMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:FourPointSevenPercentSeniorDebenturesDueTwoThousandFortyThreeMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:FourPointSevenPercentSeniorDebenturesDueTwoThousandFortyThreeMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointSevenPercentSeniorDebenturesDueTwoThousandFortySixMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:ThreePointSevenPercentSeniorDebenturesDueTwoThousandFortySixMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointSevenPercentSeniorDebenturesDueTwoThousandFortySixMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMemberlnt:ThreePointSevenPercentSeniorDebenturesDueTwoThousandFortySixMember2023-12-310000352541lnt:ThreePointFivePercentSeniorDebenturesDueTwoThousandFortyNineMemberlnt:SeniorDebenturesMember2022-12-310000352541lnt:ThreePointFivePercentSeniorDebenturesDueTwoThousandFortyNineMemberlnt:SeniorDebenturesMember2023-12-310000352541lnt:ThreePointFivePercentSeniorDebenturesDueTwoThousandFortyNineMemberlnt:SeniorDebenturesMemberlnt:IplMember2022-12-310000352541lnt:ThreePointFivePercentSeniorDebenturesDueTwoThousandFortyNineMemberlnt:SeniorDebenturesMemberlnt:IplMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointOnePercentSeniorDebenturesDueTwoThousandFiftyOneMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointOnePercentSeniorDebenturesDueTwoThousandFiftyOneMemberlnt:IplMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointOnePercentSeniorDebenturesDueTwoThousandFiftyOneMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:ThreePointOnePercentSeniorDebenturesDueTwoThousandFiftyOneMemberlnt:IplMember2023-12-310000352541lnt:SeniorDebenturesMember2023-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMember2023-12-310000352541lnt:SeniorDebenturesMember2022-12-310000352541lnt:SeniorDebenturesMemberlnt:IplMember2022-12-310000352541lnt:WplMemberlnt:ThreePointZeroFiveDebentureDueTwoThousandAndTwentySevenMemberlnt:DebenturesMember2022-12-310000352541lnt:ThreePointZeroFiveDebentureDueTwoThousandAndTwentySevenMemberlnt:DebenturesMember2022-12-310000352541lnt:ThreePointZeroFiveDebentureDueTwoThousandAndTwentySevenMemberlnt:DebenturesMember2023-12-310000352541lnt:WplMemberlnt:ThreePointZeroFiveDebentureDueTwoThousandAndTwentySevenMemberlnt:DebenturesMember2023-12-310000352541lnt:WplMemberlnt:ThreePercentDebenturesDueTwoThousandTwentyNineMemberlnt:DebenturesMember2023-12-310000352541lnt:WplMemberlnt:ThreePercentDebenturesDueTwoThousandTwentyNineMemberlnt:DebenturesMember2022-12-310000352541lnt:ThreePercentDebenturesDueTwoThousandTwentyNineMemberlnt:DebenturesMember2023-12-310000352541lnt:ThreePercentDebenturesDueTwoThousandTwentyNineMemberlnt:DebenturesMember2022-12-310000352541lnt:DebenturesMemberlnt:OnePointNineFivePercentDebenturesDueTwoThousandThirtyOneMember2023-12-310000352541lnt:WplMemberlnt:DebenturesMemberlnt:OnePointNineFivePercentDebenturesDueTwoThousandThirtyOneMember2023-12-310000352541lnt:DebenturesMemberlnt:OnePointNineFivePercentDebenturesDueTwoThousandThirtyOneMember2022-12-310000352541lnt:WplMemberlnt:DebenturesMemberlnt:OnePointNineFivePercentDebenturesDueTwoThousandThirtyOneMember2022-12-310000352541lnt:DebenturesMemberlnt:ThreePointNineFivePercentDebentureDueTwoThousandThirtyTwoMember2023-12-310000352541lnt:DebenturesMemberlnt:ThreePointNineFivePercentDebentureDueTwoThousandThirtyTwoMember2022-12-310000352541lnt:WplMemberlnt:DebenturesMemberlnt:ThreePointNineFivePercentDebentureDueTwoThousandThirtyTwoMember2022-12-310000352541lnt:WplMemberlnt:DebenturesMemberlnt:ThreePointNineFivePercentDebentureDueTwoThousandThirtyTwoMember2023-12-310000352541lnt:WplMemberlnt:FourPointNineFivePercentDebenturesDueTwoThousandThirtyThreeMemberlnt:DebenturesMember2023-12-310000352541lnt:FourPointNineFivePercentDebenturesDueTwoThousandThirtyThreeMemberlnt:DebenturesMember2023-12-310000352541lnt:FourPointNineFivePercentDebenturesDueTwoThousandThirtyThreeMemberlnt:DebenturesMember2022-12-310000352541lnt:WplMemberlnt:FourPointNineFivePercentDebenturesDueTwoThousandThirtyThreeMemberlnt:DebenturesMember2022-12-310000352541lnt:WplMemberlnt:SixPointTwoFivePercentDebentureDueTwoThousandThirtyFourMemberlnt:DebenturesMember2023-12-310000352541lnt:SixPointTwoFivePercentDebentureDueTwoThousandThirtyFourMemberlnt:DebenturesMember2022-12-310000352541lnt:WplMemberlnt:SixPointTwoFivePercentDebentureDueTwoThousandThirtyFourMemberlnt:DebenturesMember2022-12-310000352541lnt:SixPointTwoFivePercentDebentureDueTwoThousandThirtyFourMemberlnt:DebenturesMember2023-12-310000352541lnt:DebenturesMemberlnt:SixPointThreeSevenFivePercentDebentureDueTwoThousandThirtySevenMember2022-12-310000352541lnt:WplMemberlnt:SixPointThreeSevenFivePercentDebentureDueTwoThousandThirtySevenMemberlnt:DebenturesMember2023-12-310000352541lnt:DebenturesMemberlnt:SixPointThreeSevenFivePercentDebentureDueTwoThousandThirtySevenMember2023-12-310000352541lnt:WplMemberlnt:SixPointThreeSevenFivePercentDebentureDueTwoThousandThirtySevenMemberlnt:DebenturesMember2022-12-310000352541lnt:WplMemberlnt:SevenPointSixPercentDebentureDueTwoThousandThirtyEightMemberlnt:DebenturesMember2022-12-310000352541lnt:SevenPointSixPercentDebentureDueTwoThousandThirtyEightMemberlnt:DebenturesMember2022-12-310000352541lnt:SevenPointSixPercentDebentureDueTwoThousandThirtyEightMemberlnt:DebenturesMember2023-12-310000352541lnt:WplMemberlnt:SevenPointSixPercentDebentureDueTwoThousandThirtyEightMemberlnt:DebenturesMember2023-12-310000352541lnt:FourPointOnePercentDebentureDueTwoThousandFortyFourMemberMemberlnt:DebenturesMember2023-12-310000352541lnt:FourPointOnePercentDebentureDueTwoThousandFortyFourMemberMemberlnt:DebenturesMember2022-12-310000352541lnt:WplMemberlnt:FourPointOnePercentDebentureDueTwoThousandFortyFourMemberMemberlnt:DebenturesMember2023-12-310000352541lnt:WplMemberlnt:FourPointOnePercentDebentureDueTwoThousandFortyFourMemberMemberlnt:DebenturesMember2022-12-310000352541lnt:WplMemberlnt:DebenturesMemberlnt:ThreePointSixFivePercentDebenturesDueTwoThousandFiftyMember2023-12-310000352541lnt:WplMemberlnt:DebenturesMemberlnt:ThreePointSixFivePercentDebenturesDueTwoThousandFiftyMember2022-12-310000352541lnt:DebenturesMemberlnt:ThreePointSixFivePercentDebenturesDueTwoThousandFiftyMember2023-12-310000352541lnt:DebenturesMemberlnt:ThreePointSixFivePercentDebenturesDueTwoThousandFiftyMember2022-12-310000352541lnt:DebenturesMember2023-12-310000352541lnt:WplMemberlnt:DebenturesMember2023-12-310000352541lnt:DebenturesMember2022-12-310000352541lnt:WplMemberlnt:DebenturesMember2022-12-310000352541lnt:AlliantEnergyFinanceLLCMemberlnt:TermLoanCreditAgreementThroughMarchTwoThousandTwentyFourMemberlnt:TermLoanCreditAgreementMember2023-12-310000352541lnt:AlliantEnergyFinanceLLCMemberlnt:TermLoanCreditAgreementThroughMarchTwoThousandTwentyFourMemberlnt:TermLoanCreditAgreementMember2022-12-310000352541lnt:OnePointFourPercentSeniorNotesDueTwoThousandTwentySixMemberlnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMember2023-12-310000352541lnt:OnePointFourPercentSeniorNotesDueTwoThousandTwentySixMemberlnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMember2022-12-310000352541us-gaap:SeniorNotesMemberlnt:ThreePointEightSevenFivePercentSeniorNotesDueTwoThousandTwentySixMember2023-12-310000352541us-gaap:SeniorNotesMemberlnt:ThreePointEightSevenFivePercentSeniorNotesDueTwoThousandTwentySixMember2022-12-310000352541lnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMemberlnt:FourPointTwoFivePercentSeniorNotesDueTwoThousandAndTwentyEightMember2022-12-310000352541lnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMemberlnt:FourPointTwoFivePercentSeniorNotesDueTwoThousandAndTwentyEightMember2023-12-310000352541lnt:FivePointNineFivePercentSeniorNotesDueTwoThousandTwentyNineMemberlnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMember2023-12-310000352541lnt:FivePointNineFivePercentSeniorNotesDueTwoThousandTwentyNineMemberlnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMember2022-12-310000352541lnt:AlliantEnergyFinanceLLCMemberlnt:ThreePointSixPercentSeniorNotesDueTwentyThousandThirtyTwoMemberus-gaap:SeniorNotesMember2023-12-310000352541lnt:AlliantEnergyFinanceLLCMemberlnt:ThreePointSixPercentSeniorNotesDueTwentyThousandThirtyTwoMemberus-gaap:SeniorNotesMember2022-12-310000352541lnt:SeniorSecuredNotesMemberlnt:SheboyganPowerLlcMemberlnt:FivePointZeroSixPercentOtherSeniorNotesDueTwoThousandTwelveToTwoThousandTwentyFourMember2022-12-310000352541lnt:SeniorSecuredNotesMemberlnt:SheboyganPowerLlcMemberlnt:FivePointZeroSixPercentOtherSeniorNotesDueTwoThousandTwelveToTwoThousandTwentyFourMember2023-12-310000352541lnt:ThreepointsevenfiveseniornotesduetwothousandandtwentythreeMemberlnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMember2022-12-310000352541lnt:ThreepointsevenfiveseniornotesduetwothousandandtwentythreeMemberlnt:AlliantEnergyFinanceLLCMemberus-gaap:SeniorNotesMember2023-12-310000352541lnt:OtherLongTermDebtMiscellaneousMemberlnt:OnePercentAtDecemberThirtyFirstTwoThousandTwentyOneOtherLongTermDebtDueTwoThousandTwentyTwoToTwoThousandTwentyFiveMember2023-12-310000352541lnt:OtherLongTermDebtMiscellaneousMemberlnt:OnePercentAtDecemberThirtyFirstTwoThousandTwentyOneOtherLongTermDebtDueTwoThousandTwentyTwoToTwoThousandTwentyFiveMember2022-12-310000352541lnt:OtherLongTermDebtMember2023-12-310000352541lnt:OtherLongTermDebtMember2022-12-310000352541lnt:AlliantEnergyFinanceLLCMemberlnt:TermLoanCreditAgreementMemberlnt:TermLoanCreditAgreementThroughMarch2024FixedRateMember2023-12-310000352541lnt:AlliantEnergyFinanceLLCMemberlnt:TermLoanCreditAgreementThroughMarchTwoThousandTwentyFourMemberlnt:TermLoanCreditAgreementMember2023-01-012023-12-310000352541us-gaap:ConvertibleDebtMemberlnt:ThreePointEightSevenFivePercentSeniorNotesDueTwoThousandTwentySixMember2023-12-310000352541us-gaap:ConvertibleDebtMember2023-01-012023-12-31lnt:Integer0000352541srt:MaximumMemberus-gaap:ConvertibleDebtMemberlnt:ThreePointEightSevenFivePercentSeniorNotesDueTwoThousandTwentySixMember2023-01-012023-12-310000352541us-gaap:ConvertibleDebtMemberlnt:ThreePointEightSevenFivePercentSeniorNotesDueTwoThousandTwentySixMember2023-01-012023-12-310000352541lnt:AlliantEnergyFinanceLLCMember2023-12-310000352541lnt:WplMemberlnt:SheboyganFallsEnergyFacilityMember2023-01-012023-12-31lnt:lease_renewal_period_option0000352541lnt:SheboyganFallsEnergyFacilityMember2022-12-310000352541lnt:WplMemberlnt:SheboyganFallsEnergyFacilityMember2023-12-310000352541lnt:WplMemberlnt:SheboyganFallsEnergyFacilityMember2022-12-310000352541lnt:LeasedLandForSolarGenerationMember2022-12-310000352541lnt:LeasedLandForSolarGenerationMember2023-12-310000352541lnt:IplMemberlnt:LeasedLandForSolarGenerationMember2023-12-310000352541lnt:WplMemberlnt:LeasedLandForSolarGenerationMember2023-12-310000352541lnt:IplMemberlnt:LeasedLandForSolarGenerationMember2022-12-310000352541lnt:WplMemberlnt:LeasedLandForSolarGenerationMember2022-12-310000352541lnt:RetailResidentialMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:RetailResidentialMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:RetailResidentialMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:RetailResidentialMemberlnt:IplMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:RetailResidentialMemberlnt:IplMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:RetailResidentialMemberlnt:IplMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:WplMemberlnt:RetailResidentialMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:WplMemberlnt:RetailResidentialMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:WplMemberlnt:RetailResidentialMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:RetailCommercialMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:RetailCommercialMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:RetailCommercialMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:RetailCommercialMemberlnt:IplMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:RetailCommercialMemberlnt:IplMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:RetailCommercialMemberlnt:IplMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:WplMemberlnt:RetailCommercialMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:WplMemberlnt:RetailCommercialMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:WplMemberlnt:RetailCommercialMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:ElectricMemberlnt:RetailIndustrialMember2023-01-012023-12-310000352541lnt:ElectricMemberlnt:RetailIndustrialMember2022-01-012022-12-310000352541lnt:ElectricMemberlnt:RetailIndustrialMember2021-01-012021-12-310000352541lnt:IplMemberlnt:ElectricMemberlnt:RetailIndustrialMember2023-01-012023-12-310000352541lnt:IplMemberlnt:ElectricMemberlnt:RetailIndustrialMember2022-01-012022-12-310000352541lnt:IplMemberlnt:ElectricMemberlnt:RetailIndustrialMember2021-01-012021-12-310000352541lnt:WplMemberlnt:ElectricMemberlnt:RetailIndustrialMember2023-01-012023-12-310000352541lnt:WplMemberlnt:ElectricMemberlnt:RetailIndustrialMember2022-01-012022-12-310000352541lnt:WplMemberlnt:ElectricMemberlnt:RetailIndustrialMember2021-01-012021-12-310000352541lnt:WholesaleMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:WholesaleMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:WholesaleMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:WholesaleMemberlnt:IplMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:WholesaleMemberlnt:IplMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:WholesaleMemberlnt:IplMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:WplMemberlnt:WholesaleMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:WplMemberlnt:WholesaleMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:WplMemberlnt:WholesaleMemberlnt:ElectricMember2021-01-012021-12-310000352541us-gaap:OtherCustomerMemberlnt:ElectricMember2023-01-012023-12-310000352541us-gaap:OtherCustomerMemberlnt:ElectricMember2022-01-012022-12-310000352541us-gaap:OtherCustomerMemberlnt:ElectricMember2021-01-012021-12-310000352541us-gaap:OtherCustomerMemberlnt:IplMemberlnt:ElectricMember2023-01-012023-12-310000352541us-gaap:OtherCustomerMemberlnt:IplMemberlnt:ElectricMember2022-01-012022-12-310000352541us-gaap:OtherCustomerMemberlnt:IplMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:ElectricMember2023-01-012023-12-310000352541lnt:ElectricMember2022-01-012022-12-310000352541lnt:ElectricMember2021-01-012021-12-310000352541lnt:IplMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:IplMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:IplMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:WplMemberlnt:ElectricMember2023-01-012023-12-310000352541lnt:WplMemberlnt:ElectricMember2022-01-012022-12-310000352541lnt:WplMemberlnt:ElectricMember2021-01-012021-12-310000352541lnt:RetailResidentialMemberlnt:GasMember2023-01-012023-12-310000352541lnt:RetailResidentialMemberlnt:GasMember2022-01-012022-12-310000352541lnt:RetailResidentialMemberlnt:GasMember2021-01-012021-12-310000352541lnt:RetailResidentialMemberlnt:GasMemberlnt:IplMember2023-01-012023-12-310000352541lnt:RetailResidentialMemberlnt:GasMemberlnt:IplMember2022-01-012022-12-310000352541lnt:RetailResidentialMemberlnt:GasMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberlnt:RetailResidentialMemberlnt:GasMember2023-01-012023-12-310000352541lnt:WplMemberlnt:RetailResidentialMemberlnt:GasMember2022-01-012022-12-310000352541lnt:WplMemberlnt:RetailResidentialMemberlnt:GasMember2021-01-012021-12-310000352541lnt:GasMemberlnt:RetailCommercialMember2023-01-012023-12-310000352541lnt:GasMemberlnt:RetailCommercialMember2022-01-012022-12-310000352541lnt:GasMemberlnt:RetailCommercialMember2021-01-012021-12-310000352541lnt:GasMemberlnt:RetailCommercialMemberlnt:IplMember2023-01-012023-12-310000352541lnt:GasMemberlnt:RetailCommercialMemberlnt:IplMember2022-01-012022-12-310000352541lnt:GasMemberlnt:RetailCommercialMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberlnt:GasMemberlnt:RetailCommercialMember2023-01-012023-12-310000352541lnt:WplMemberlnt:GasMemberlnt:RetailCommercialMember2022-01-012022-12-310000352541lnt:WplMemberlnt:GasMemberlnt:RetailCommercialMember2021-01-012021-12-310000352541lnt:GasMemberlnt:RetailIndustrialMember2023-01-012023-12-310000352541lnt:GasMemberlnt:RetailIndustrialMember2022-01-012022-12-310000352541lnt:GasMemberlnt:RetailIndustrialMember2021-01-012021-12-310000352541lnt:GasMemberlnt:IplMemberlnt:RetailIndustrialMember2023-01-012023-12-310000352541lnt:GasMemberlnt:IplMemberlnt:RetailIndustrialMember2022-01-012022-12-310000352541lnt:GasMemberlnt:IplMemberlnt:RetailIndustrialMember2021-01-012021-12-310000352541lnt:WplMemberlnt:GasMemberlnt:RetailIndustrialMember2023-01-012023-12-310000352541lnt:WplMemberlnt:GasMemberlnt:RetailIndustrialMember2022-01-012022-12-310000352541lnt:WplMemberlnt:GasMemberlnt:RetailIndustrialMember2021-01-012021-12-310000352541us-gaap:OtherCustomerMemberlnt:GasMember2023-01-012023-12-310000352541us-gaap:OtherCustomerMemberlnt:GasMember2022-01-012022-12-310000352541us-gaap:OtherCustomerMemberlnt:GasMember2021-01-012021-12-310000352541us-gaap:OtherCustomerMemberlnt:GasMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:OtherCustomerMemberlnt:GasMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:OtherCustomerMemberlnt:GasMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:GasMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:GasMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:GasMember2021-01-012021-12-310000352541lnt:GasMember2023-01-012023-12-310000352541lnt:GasMember2022-01-012022-12-310000352541lnt:GasMember2021-01-012021-12-310000352541lnt:GasMemberlnt:IplMember2023-01-012023-12-310000352541lnt:GasMemberlnt:IplMember2022-01-012022-12-310000352541lnt:GasMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberlnt:GasMember2023-01-012023-12-310000352541lnt:WplMemberlnt:GasMember2022-01-012022-12-310000352541lnt:WplMemberlnt:GasMember2021-01-012021-12-310000352541lnt:SteamMemberlnt:OtherUtilityMember2023-01-012023-12-310000352541lnt:SteamMemberlnt:OtherUtilityMember2022-01-012022-12-310000352541lnt:SteamMemberlnt:OtherUtilityMember2021-01-012021-12-310000352541lnt:SteamMemberlnt:IplMemberlnt:OtherUtilityMember2023-01-012023-12-310000352541lnt:SteamMemberlnt:IplMemberlnt:OtherUtilityMember2022-01-012022-12-310000352541lnt:SteamMemberlnt:IplMemberlnt:OtherUtilityMember2021-01-012021-12-310000352541us-gaap:OtherCustomerMemberlnt:OtherUtilityMember2023-01-012023-12-310000352541us-gaap:OtherCustomerMemberlnt:OtherUtilityMember2022-01-012022-12-310000352541us-gaap:OtherCustomerMemberlnt:OtherUtilityMember2021-01-012021-12-310000352541us-gaap:OtherCustomerMemberlnt:IplMemberlnt:OtherUtilityMember2023-01-012023-12-310000352541us-gaap:OtherCustomerMemberlnt:IplMemberlnt:OtherUtilityMember2022-01-012022-12-310000352541us-gaap:OtherCustomerMemberlnt:IplMemberlnt:OtherUtilityMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:OtherUtilityMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:OtherUtilityMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:OtherCustomerMemberlnt:OtherUtilityMember2021-01-012021-12-310000352541lnt:OtherUtilityMember2023-01-012023-12-310000352541lnt:OtherUtilityMember2022-01-012022-12-310000352541lnt:OtherUtilityMember2021-01-012021-12-310000352541lnt:IplMemberlnt:OtherUtilityMember2023-01-012023-12-310000352541lnt:IplMemberlnt:OtherUtilityMember2022-01-012022-12-310000352541lnt:IplMemberlnt:OtherUtilityMember2021-01-012021-12-310000352541lnt:WplMemberlnt:OtherUtilityMember2023-01-012023-12-310000352541lnt:WplMemberlnt:OtherUtilityMember2022-01-012022-12-310000352541lnt:WplMemberlnt:OtherUtilityMember2021-01-012021-12-310000352541us-gaap:OtherCustomerMemberus-gaap:AllOtherSegmentsMember2022-01-012022-12-310000352541us-gaap:OtherCustomerMemberus-gaap:AllOtherSegmentsMember2021-01-012021-12-310000352541us-gaap:AllOtherSegmentsMember2023-01-012023-12-310000352541us-gaap:AllOtherSegmentsMember2022-01-012022-12-310000352541us-gaap:AllOtherSegmentsMember2021-01-012021-12-310000352541lnt:IplMemberlnt:InvestmentInAtcMember2023-12-310000352541lnt:IplMemberlnt:InvestmentInAtcMember2022-12-310000352541lnt:WplMemberlnt:InvestmentInAtcMember2023-12-310000352541lnt:WplMemberlnt:InvestmentInAtcMember2022-12-310000352541us-gaap:StateAndLocalJurisdictionMember2023-12-310000352541us-gaap:StateAndLocalJurisdictionMemberlnt:IplMember2023-12-310000352541lnt:WplMemberus-gaap:StateAndLocalJurisdictionMember2023-12-310000352541us-gaap:DomesticCountryMember2023-12-310000352541us-gaap:DomesticCountryMemberlnt:IplMember2023-12-310000352541lnt:WplMemberus-gaap:DomesticCountryMember2023-12-310000352541us-gaap:StateAndLocalJurisdictionMember2020-01-012020-12-310000352541us-gaap:StateAndLocalJurisdictionMember2021-01-012021-12-310000352541srt:ScenarioForecastMemberus-gaap:StateAndLocalJurisdictionMember2025-01-012025-12-310000352541us-gaap:StateAndLocalJurisdictionMember2023-01-012023-12-310000352541srt:ScenarioForecastMemberus-gaap:StateAndLocalJurisdictionMember2024-01-012024-12-310000352541us-gaap:DeferredIncomeTaxChargesMember2022-01-012022-12-310000352541us-gaap:DeferredIncomeTaxChargesMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:DeferredIncomeTaxChargesMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:DeferredIncomeTaxChargesMember2023-01-012023-12-310000352541us-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:PensionPlansDefinedBenefitMember2021-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-12-310000352541us-gaap:PensionPlansDefinedBenefitMember2023-01-012023-12-310000352541us-gaap:PensionPlansDefinedBenefitMember2022-01-012022-12-310000352541us-gaap:PensionPlansDefinedBenefitMember2021-01-012021-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-01-012023-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-01-012022-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-01-012021-12-310000352541srt:MinimumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541srt:MaximumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541srt:MinimumMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541srt:MaximumMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541srt:MinimumMemberus-gaap:PensionPlansDefinedBenefitMember2021-12-310000352541srt:MaximumMemberus-gaap:PensionPlansDefinedBenefitMember2021-12-310000352541lnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2021-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-12-310000352541lnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2023-01-012023-12-310000352541lnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2022-01-012022-12-310000352541lnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2021-01-012021-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-01-012023-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-01-012022-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:PensionPlansDefinedBenefitMember2021-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-12-310000352541lnt:WplMemberus-gaap:PensionPlansDefinedBenefitMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:PensionPlansDefinedBenefitMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:PensionPlansDefinedBenefitMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-01-012021-12-310000352541srt:ScenarioForecastMemberus-gaap:PensionPlansDefinedBenefitMember2024-12-310000352541srt:ScenarioForecastMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2024-12-310000352541lnt:WplMembersrt:ScenarioForecastMemberus-gaap:PensionPlansDefinedBenefitMember2024-12-310000352541srt:ScenarioForecastMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2024-12-310000352541srt:ScenarioForecastMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2024-12-310000352541lnt:WplMembersrt:ScenarioForecastMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2024-12-310000352541us-gaap:CashAndCashEquivalentsMembersrt:MinimumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMembersrt:MaximumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541srt:MinimumMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541srt:MaximumMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMembersrt:MinimumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMembersrt:MaximumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMembersrt:MinimumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMembersrt:MaximumMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMembersrt:MinimumMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMembersrt:MaximumMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541srt:MinimumMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541srt:MaximumMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMembersrt:MinimumMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMembersrt:MaximumMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel1Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel1Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberus-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberus-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMemberlnt:AccruedInvestmentIncomeMember2023-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMemberlnt:AccruedInvestmentIncomeMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:IplMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:IplMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberus-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberus-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberlnt:IplMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMemberlnt:AccruedInvestmentIncomeMember2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMemberlnt:AccruedInvestmentIncomeMember2022-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberlnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberlnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:SubtotalMemberlnt:WplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberlnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberlnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:SubtotalMemberlnt:WplMemberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMemberlnt:AccruedInvestmentIncomeMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:PensionPlansDefinedBenefitMemberlnt:AccruedInvestmentIncomeMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541us-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541us-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:GlobalAssetAllocationSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:GlobalAssetAllocationSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:CashAndCashEquivalentsMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FixedIncomeSecuritiesMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541us-gaap:FairValueMeasuredAtNetAssetValuePerShareMemberlnt:IplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:CashAndCashEquivalentsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2023-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMember2022-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:DefinedBenefitPlanEquitySecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel12And3Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FixedIncomeSecuritiesMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310000352541lnt:WplMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMember2023-01-012023-12-310000352541us-gaap:OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:OtherPensionPlansPostretirementOrSupplementalPlansDefinedBenefitMember2023-01-012023-12-310000352541lnt:OmnibusIncentivePlanMember2023-12-310000352541srt:MinimumMember2023-01-012023-12-310000352541srt:MaximumMember2023-01-012023-12-310000352541lnt:OmnibusIncentivePlanMember2023-01-012023-12-310000352541us-gaap:PerformanceSharesMember2023-01-012023-12-310000352541srt:MinimumMemberus-gaap:PerformanceSharesMember2023-01-012023-12-310000352541srt:MaximumMemberus-gaap:PerformanceSharesMember2023-01-012023-12-310000352541us-gaap:PerformanceSharesMember2022-12-310000352541us-gaap:PerformanceSharesMember2021-12-310000352541us-gaap:PerformanceSharesMember2020-12-310000352541us-gaap:PerformanceSharesMember2022-01-012022-12-310000352541us-gaap:PerformanceSharesMember2021-01-012021-12-310000352541us-gaap:PerformanceSharesMember2023-12-310000352541us-gaap:RestrictedStockUnitsRSUMember2023-01-012023-12-310000352541us-gaap:RestrictedStockUnitsRSUMember2022-12-310000352541us-gaap:RestrictedStockUnitsRSUMember2021-12-310000352541us-gaap:RestrictedStockUnitsRSUMember2020-12-310000352541us-gaap:RestrictedStockUnitsRSUMember2022-01-012022-12-310000352541us-gaap:RestrictedStockUnitsRSUMember2021-01-012021-12-310000352541us-gaap:RestrictedStockUnitsRSUMember2023-12-310000352541lnt:PerformanceRestrictedStockUnitMember2023-01-012023-12-310000352541srt:MinimumMemberlnt:PerformanceRestrictedStockUnitMember2023-01-012023-12-310000352541srt:MaximumMemberlnt:PerformanceRestrictedStockUnitMember2023-01-012023-12-310000352541lnt:PerformanceRestrictedStockUnitMember2022-12-310000352541lnt:PerformanceRestrictedStockUnitMember2021-12-310000352541lnt:PerformanceRestrictedStockUnitMember2020-12-310000352541lnt:PerformanceRestrictedStockUnitMember2022-01-012022-12-310000352541lnt:PerformanceRestrictedStockUnitMember2021-01-012021-12-310000352541lnt:PerformanceRestrictedStockUnitMember2023-12-310000352541us-gaap:ElectricityMemberus-gaap:CommodityMember2023-01-012023-12-31utr:MWh0000352541us-gaap:CommodityMemberlnt:FtrsMwhsMember2023-01-012023-12-310000352541us-gaap:CommodityMembersrt:NaturalGasPerThousandCubicFeetMember2023-12-31lnt:Dekatherms0000352541us-gaap:ElectricityMemberus-gaap:CommodityMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:CommodityMemberlnt:IplMemberlnt:FtrsMwhsMember2023-01-012023-12-310000352541us-gaap:CommodityMemberlnt:IplMembersrt:NaturalGasPerThousandCubicFeetMember2023-12-310000352541lnt:WplMemberus-gaap:ElectricityMemberus-gaap:CommodityMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:CommodityMemberlnt:FtrsMwhsMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:CommodityMembersrt:NaturalGasPerThousandCubicFeetMember2023-12-310000352541us-gaap:CommodityContractMember2023-12-310000352541us-gaap:CommodityContractMember2022-12-310000352541lnt:IplMemberus-gaap:CommodityContractMember2023-12-310000352541lnt:IplMemberus-gaap:CommodityContractMember2022-12-310000352541lnt:WplMemberus-gaap:CommodityContractMember2023-12-310000352541lnt:WplMemberus-gaap:CommodityContractMember2022-12-310000352541lnt:AlliantEnergyFinanceLLCMemberus-gaap:InterestRateSwapMemberlnt:TermLoanCreditAgreementMember2023-12-310000352541lnt:AlliantEnergyFinanceLLCMemberus-gaap:InterestRateSwapMemberlnt:TermLoanCreditAgreementMember2023-01-012023-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMember2023-12-310000352541us-gaap:FairValueInputsLevel1Member2023-12-310000352541us-gaap:FairValueInputsLevel2Member2023-12-310000352541us-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMember2022-12-310000352541us-gaap:FairValueInputsLevel1Member2022-12-310000352541us-gaap:FairValueInputsLevel2Member2022-12-310000352541us-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberus-gaap:CommodityContractMember2023-12-310000352541us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CommodityContractMember2023-12-310000352541us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberus-gaap:CommodityContractMember2022-12-310000352541us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel1Member2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:CommodityContractMember2022-12-310000352541us-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberus-gaap:InterestRateSwapMember2023-12-310000352541us-gaap:InterestRateSwapMemberus-gaap:FairValueInputsLevel1Member2023-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:InterestRateSwapMember2023-12-310000352541us-gaap:InterestRateSwapMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:InterestRateSwapMember2023-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberus-gaap:InterestRateSwapMember2022-12-310000352541us-gaap:InterestRateSwapMemberus-gaap:FairValueInputsLevel1Member2022-12-310000352541us-gaap:FairValueInputsLevel2Memberus-gaap:InterestRateSwapMember2022-12-310000352541us-gaap:InterestRateSwapMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:InterestRateSwapMember2022-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberlnt:IplMember2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Member2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMember2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberlnt:IplMember2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Member2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMember2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberlnt:IplMemberus-gaap:CommodityContractMember2023-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:CommodityContractMember2023-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:CommodityContractMember2023-12-310000352541lnt:IplMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541us-gaap:CarryingReportedAmountFairValueDisclosureMemberlnt:IplMemberus-gaap:CommodityContractMember2022-12-310000352541lnt:IplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:CommodityContractMember2022-12-310000352541us-gaap:FairValueInputsLevel2Memberlnt:IplMemberus-gaap:CommodityContractMember2022-12-310000352541lnt:IplMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:CarryingReportedAmountFairValueDisclosureMemberus-gaap:CommodityContractMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:CommodityContractMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CommodityContractMember2023-12-310000352541lnt:WplMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:CarryingReportedAmountFairValueDisclosureMemberus-gaap:CommodityContractMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Memberus-gaap:CommodityContractMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CommodityContractMember2022-12-310000352541lnt:WplMemberus-gaap:CommodityContractMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541lnt:WplMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Member2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Member2023-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel3Member2023-12-310000352541lnt:WplMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel1Member2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel2Member2022-12-310000352541lnt:WplMemberus-gaap:FairValueInputsLevel3Member2022-12-310000352541us-gaap:CommodityContractMember2022-12-310000352541us-gaap:CommodityContractMember2021-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMember2022-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMember2021-12-310000352541us-gaap:CommodityContractMember2023-01-012023-12-310000352541us-gaap:CommodityContractMember2022-01-012022-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMember2023-01-012023-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMember2022-01-012022-12-310000352541us-gaap:CommodityContractMember2023-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMember2023-12-310000352541us-gaap:CommodityContractMemberlnt:IplMember2022-12-310000352541us-gaap:CommodityContractMemberlnt:IplMember2021-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMemberlnt:IplMember2022-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMemberlnt:IplMember2021-12-310000352541us-gaap:CommodityContractMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:CommodityContractMemberlnt:IplMember2022-01-012022-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMemberlnt:IplMember2023-01-012023-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:CommodityContractMemberlnt:IplMember2023-12-310000352541lnt:DeferredProceedsOfReceivablesSoldMemberlnt:IplMember2023-12-310000352541lnt:WplMemberus-gaap:CommodityContractMember2022-12-310000352541lnt:WplMemberus-gaap:CommodityContractMember2021-12-310000352541lnt:WplMemberus-gaap:CommodityContractMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:CommodityContractMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:CommodityContractMember2023-12-310000352541us-gaap:CommodityContractMemberlnt:ExcludingFinancialTransmissionRightsMember2023-12-310000352541us-gaap:CommodityContractMemberlnt:FinancialTransmissionRightsMember2023-12-310000352541us-gaap:CommodityContractMemberlnt:IplMemberlnt:ExcludingFinancialTransmissionRightsMember2023-12-310000352541us-gaap:CommodityContractMemberlnt:IplMemberlnt:FinancialTransmissionRightsMember2023-12-310000352541lnt:WplMemberus-gaap:CommodityContractMemberlnt:ExcludingFinancialTransmissionRightsMember2023-12-310000352541lnt:WplMemberus-gaap:CommodityContractMemberlnt:FinancialTransmissionRightsMember2023-12-310000352541us-gaap:CommodityContractMemberlnt:ExcludingFinancialTransmissionRightsMember2022-12-310000352541us-gaap:CommodityContractMemberlnt:FinancialTransmissionRightsMember2022-12-310000352541us-gaap:CommodityContractMemberlnt:IplMemberlnt:ExcludingFinancialTransmissionRightsMember2022-12-310000352541us-gaap:CommodityContractMemberlnt:IplMemberlnt:FinancialTransmissionRightsMember2022-12-310000352541lnt:WplMemberus-gaap:CommodityContractMemberlnt:ExcludingFinancialTransmissionRightsMember2022-12-310000352541lnt:WplMemberus-gaap:CommodityContractMemberlnt:FinancialTransmissionRightsMember2022-12-310000352541lnt:CapitalPurchaseObligationMember2023-01-012023-12-310000352541lnt:CapitalPurchaseObligationMemberlnt:IplMember2023-01-012023-12-310000352541lnt:WplMemberlnt:CapitalPurchaseObligationMember2023-01-012023-12-310000352541us-gaap:PublicUtilitiesInventoryNaturalGasMember2023-12-310000352541us-gaap:CoalSupplyAgreementsMember2023-12-310000352541lnt:LongTermPurchaseCommitmentsOtherMember2023-12-310000352541lnt:IplMemberus-gaap:PublicUtilitiesInventoryNaturalGasMember2023-12-310000352541lnt:IplMemberus-gaap:CoalSupplyAgreementsMember2023-12-310000352541lnt:LongTermPurchaseCommitmentsOtherMemberlnt:IplMember2023-12-310000352541lnt:WplMemberus-gaap:PublicUtilitiesInventoryNaturalGasMember2023-12-310000352541lnt:WplMemberus-gaap:CoalSupplyAgreementsMember2023-12-310000352541lnt:WplMemberlnt:LongTermPurchaseCommitmentsOtherMember2023-12-310000352541lnt:WhitingPetroleumAffiliateMember2023-01-012023-12-310000352541lnt:WhitingPetroleumAffiliateMember2023-12-310000352541us-gaap:IndemnificationGuaranteeMember2023-12-310000352541lnt:PurchasedPowerMemberus-gaap:IndemnificationGuaranteeMember2023-12-310000352541us-gaap:NaturalGasProcessingPlantMembersrt:MinimumMember2023-01-012023-12-310000352541us-gaap:NaturalGasProcessingPlantMembersrt:MaximumMember2023-01-012023-12-310000352541us-gaap:NaturalGasProcessingPlantMemberlnt:IplMembersrt:MinimumMember2023-01-012023-12-310000352541us-gaap:NaturalGasProcessingPlantMembersrt:MaximumMemberlnt:IplMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:NaturalGasProcessingPlantMembersrt:MinimumMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:NaturalGasProcessingPlantMembersrt:MaximumMember2023-01-012023-12-310000352541us-gaap:NaturalGasProcessingPlantMember2023-12-310000352541us-gaap:NaturalGasProcessingPlantMemberlnt:IplMember2023-12-310000352541lnt:WplMemberus-gaap:NaturalGasProcessingPlantMember2023-12-310000352541lnt:FederalEnergyRegulatoryCommissionMember2019-01-012019-12-310000352541lnt:FederalEnergyRegulatoryCommissionMember2020-01-012020-12-310000352541lnt:FederalEnergyRegulatoryCommissionMember2022-01-012022-12-310000352541us-gaap:WorkforceSubjectToCollectiveBargainingArrangementsMember2023-12-310000352541lnt:IplMemberus-gaap:WorkforceSubjectToCollectiveBargainingArrangementsMember2023-12-310000352541lnt:WplMemberus-gaap:WorkforceSubjectToCollectiveBargainingArrangementsMember2023-12-310000352541us-gaap:WorkforceSubjectToCollectiveBargainingArrangementsExpiringWithinOneYearMember2023-12-310000352541lnt:IplMemberus-gaap:WorkforceSubjectToCollectiveBargainingArrangementsExpiringWithinOneYearMember2023-12-310000352541lnt:UtilityBusinessMember2023-01-012023-12-31lnt:segment0000352541us-gaap:RegulatedOperationMember2023-01-012023-12-310000352541lnt:ElectricMember2023-12-310000352541lnt:GasMember2023-12-310000352541lnt:OtherUtilityMember2023-12-310000352541us-gaap:RegulatedOperationMember2023-12-310000352541us-gaap:AllOtherSegmentsMember2023-12-310000352541us-gaap:RegulatedOperationMember2022-01-012022-12-310000352541lnt:ElectricMember2022-12-310000352541lnt:GasMember2022-12-310000352541lnt:OtherUtilityMember2022-12-310000352541us-gaap:RegulatedOperationMember2022-12-310000352541us-gaap:AllOtherSegmentsMember2022-12-310000352541us-gaap:RegulatedOperationMember2021-01-012021-12-310000352541lnt:ElectricMember2021-12-310000352541lnt:GasMember2021-12-310000352541lnt:OtherUtilityMember2021-12-310000352541us-gaap:RegulatedOperationMember2021-12-310000352541us-gaap:AllOtherSegmentsMember2021-12-310000352541us-gaap:RegulatedOperationMemberlnt:IplMember2023-01-012023-12-310000352541lnt:IplMemberlnt:ElectricMember2023-12-310000352541lnt:GasMemberlnt:IplMember2023-12-310000352541lnt:IplMemberlnt:OtherUtilityMember2023-12-310000352541us-gaap:RegulatedOperationMemberlnt:IplMember2023-12-310000352541us-gaap:RegulatedOperationMemberlnt:IplMember2022-01-012022-12-310000352541lnt:IplMemberlnt:ElectricMember2022-12-310000352541lnt:GasMemberlnt:IplMember2022-12-310000352541lnt:IplMemberlnt:OtherUtilityMember2022-12-310000352541us-gaap:RegulatedOperationMemberlnt:IplMember2022-12-310000352541us-gaap:RegulatedOperationMemberlnt:IplMember2021-01-012021-12-310000352541lnt:IplMemberlnt:ElectricMember2021-12-310000352541lnt:GasMemberlnt:IplMember2021-12-310000352541lnt:IplMemberlnt:OtherUtilityMember2021-12-310000352541us-gaap:RegulatedOperationMemberlnt:IplMember2021-12-310000352541lnt:WplMemberus-gaap:RegulatedOperationMember2023-01-012023-12-310000352541lnt:WplMemberlnt:ElectricMember2023-12-310000352541lnt:WplMemberlnt:GasMember2023-12-310000352541lnt:WplMemberlnt:OtherUtilityMember2023-12-310000352541lnt:WplMemberus-gaap:RegulatedOperationMember2023-12-310000352541lnt:WplMemberus-gaap:RegulatedOperationMember2022-01-012022-12-310000352541lnt:WplMemberlnt:ElectricMember2022-12-310000352541lnt:WplMemberlnt:GasMember2022-12-310000352541lnt:WplMemberlnt:OtherUtilityMember2022-12-310000352541lnt:WplMemberus-gaap:RegulatedOperationMember2022-12-310000352541lnt:WplMemberus-gaap:RegulatedOperationMember2021-01-012021-12-310000352541lnt:WplMemberlnt:ElectricMember2021-12-310000352541lnt:WplMemberlnt:GasMember2021-12-310000352541lnt:WplMemberlnt:OtherUtilityMember2021-12-310000352541lnt:WplMemberus-gaap:RegulatedOperationMember2021-12-310000352541lnt:AdministrativeandGeneralServicesBillingsMemberlnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMember2023-01-012023-12-310000352541lnt:AdministrativeandGeneralServicesBillingsMemberlnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMember2022-01-012022-12-310000352541lnt:AdministrativeandGeneralServicesBillingsMemberlnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMember2021-01-012021-12-310000352541lnt:WplMemberlnt:AdministrativeandGeneralServicesBillingsMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMember2023-01-012023-12-310000352541lnt:WplMemberlnt:AdministrativeandGeneralServicesBillingsMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMember2022-01-012022-12-310000352541lnt:WplMemberlnt:AdministrativeandGeneralServicesBillingsMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMember2021-01-012021-12-310000352541lnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMemberlnt:TransmissionSalesCreditedMember2023-01-012023-12-310000352541lnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMemberlnt:TransmissionSalesCreditedMember2022-01-012022-12-310000352541lnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMemberlnt:TransmissionSalesCreditedMember2021-01-012021-12-310000352541lnt:WplMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMemberlnt:TransmissionSalesCreditedMember2023-01-012023-12-310000352541lnt:WplMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMemberlnt:TransmissionSalesCreditedMember2022-01-012022-12-310000352541lnt:WplMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMemberlnt:TransmissionSalesCreditedMember2021-01-012021-12-310000352541lnt:TransmissionPurchasesBilledMemberlnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMember2023-01-012023-12-310000352541lnt:TransmissionPurchasesBilledMemberlnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMember2022-01-012022-12-310000352541lnt:TransmissionPurchasesBilledMemberlnt:CorporateServicesMemberlnt:IplMemberus-gaap:SubsidiaryOfCommonParentMember2021-01-012021-12-310000352541lnt:WplMemberlnt:TransmissionPurchasesBilledMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMember2023-01-012023-12-310000352541lnt:WplMemberlnt:TransmissionPurchasesBilledMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMember2022-01-012022-12-310000352541lnt:WplMemberlnt:TransmissionPurchasesBilledMemberlnt:CorporateServicesMemberus-gaap:SubsidiaryOfCommonParentMember2021-01-012021-12-310000352541us-gaap:RelatedPartyMemberlnt:CorporateServicesMemberlnt:IplMember2023-12-310000352541us-gaap:RelatedPartyMemberlnt:CorporateServicesMemberlnt:IplMember2022-12-310000352541lnt:WplMemberus-gaap:RelatedPartyMemberlnt:CorporateServicesMember2023-12-310000352541lnt:WplMemberus-gaap:RelatedPartyMemberlnt:CorporateServicesMember2022-12-310000352541lnt:WplMemberlnt:AtcBillingsToWplMemberlnt:AmericanTransmissionCompanyLlcAtcMemberus-gaap:EquityMethodInvestmentsMember2023-01-012023-12-310000352541lnt:WplMemberlnt:AtcBillingsToWplMemberlnt:AmericanTransmissionCompanyLlcAtcMemberus-gaap:EquityMethodInvestmentsMember2022-01-012022-12-310000352541lnt:WplMemberlnt:AtcBillingsToWplMemberlnt:AmericanTransmissionCompanyLlcAtcMemberus-gaap:EquityMethodInvestmentsMember2021-01-012021-12-310000352541lnt:WplBillingsToAtcMemberlnt:WplMemberlnt:AmericanTransmissionCompanyLlcAtcMemberus-gaap:EquityMethodInvestmentsMember2023-01-012023-12-310000352541lnt:WplBillingsToAtcMemberlnt:WplMemberlnt:AmericanTransmissionCompanyLlcAtcMemberus-gaap:EquityMethodInvestmentsMember2022-01-012022-12-310000352541lnt:WplBillingsToAtcMemberlnt:WplMemberlnt:AmericanTransmissionCompanyLlcAtcMemberus-gaap:EquityMethodInvestmentsMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:RelatedPartyMemberlnt:ATCLLCMemberlnt:WplOwedAtcMember2023-12-310000352541lnt:WplMemberus-gaap:RelatedPartyMemberlnt:ATCLLCMemberlnt:WplOwedAtcMember2022-12-310000352541srt:ParentCompanyMember2023-01-012023-12-310000352541srt:ParentCompanyMember2022-01-012022-12-310000352541srt:ParentCompanyMember2021-01-012021-12-310000352541srt:ParentCompanyMember2022-12-310000352541srt:ParentCompanyMember2021-12-310000352541srt:ParentCompanyMember2020-12-310000352541us-gaap:AllowanceForCreditLossMember2022-12-310000352541us-gaap:AllowanceForCreditLossMember2023-01-012023-12-310000352541us-gaap:AllowanceForCreditLossMember2023-12-310000352541us-gaap:AllowanceForCreditLossMember2021-12-310000352541us-gaap:AllowanceForCreditLossMember2022-01-012022-12-310000352541us-gaap:AllowanceForCreditLossMember2020-12-310000352541us-gaap:AllowanceForCreditLossMember2021-01-012021-12-310000352541us-gaap:AllowanceForCreditLossMemberlnt:IplMember2022-12-310000352541us-gaap:AllowanceForCreditLossMemberlnt:IplMember2023-01-012023-12-310000352541us-gaap:AllowanceForCreditLossMemberlnt:IplMember2023-12-310000352541us-gaap:AllowanceForCreditLossMemberlnt:IplMember2021-12-310000352541us-gaap:AllowanceForCreditLossMemberlnt:IplMember2022-01-012022-12-310000352541us-gaap:AllowanceForCreditLossMemberlnt:IplMember2020-12-310000352541us-gaap:AllowanceForCreditLossMemberlnt:IplMember2021-01-012021-12-310000352541lnt:WplMemberus-gaap:AllowanceForCreditLossMember2022-12-310000352541lnt:WplMemberus-gaap:AllowanceForCreditLossMember2023-01-012023-12-310000352541lnt:WplMemberus-gaap:AllowanceForCreditLossMember2023-12-310000352541lnt:WplMemberus-gaap:AllowanceForCreditLossMember2021-12-310000352541lnt:WplMemberus-gaap:AllowanceForCreditLossMember2022-01-012022-12-310000352541lnt:WplMemberus-gaap:AllowanceForCreditLossMember2020-12-310000352541lnt:WplMemberus-gaap:AllowanceForCreditLossMember2021-01-012021-12-31