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  <xsd:element name="AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsTax" id="pfg_AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AvailableForSaleDebtSecuritiesHedgingNet" id="pfg_AvailableForSaleDebtSecuritiesHedgingNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceedsAbstract" id="pfg_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceedsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="BackStopFacilityOutstandingBalances" id="pfg_BackStopFacilityOutstandingBalances" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="BackStopFacilitySupportForCommercialPaperProgramPercent" id="pfg_BackStopFacilitySupportForCommercialPaperProgramPercent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="CapitalGainsLossesDistributed" id="pfg_CapitalGainsLossesDistributed" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="CashAndCashEquivalentsMaximumMaturityPeriod" id="pfg_CashAndCashEquivalentsMaximumMaturityPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CashCollateralLiabilityFairValueDisclosure" id="pfg_CashCollateralLiabilityFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CashCollateralReceivedAssociatedWithDerivatives" id="pfg_CashCollateralReceivedAssociatedWithDerivatives" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="CashReceivedFromSharesIssued" id="pfg_CashReceivedFromSharesIssued" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ClosedBlockOperationsBenefitClaimsAndSettlementExpenses" id="pfg_ClosedBlockOperationsBenefitClaimsAndSettlementExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ConsolidatedVariableInterestEntityAssetsLiabilitiesTable" id="pfg_ConsolidatedVariableInterestEntityAssetsLiabilitiesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContractholderAndPolicyholderLiabilitiesPolicyTextBlock" id="pfg_ContractholderAndPolicyholderLiabilitiesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContractholderFunds" id="pfg_ContractholderFunds" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CreditDerivativeSoldNotional" id="pfg_CreditDerivativeSoldNotional" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CreditDerivativesSoldFairValue" id="pfg_CreditDerivativesSoldFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CreditDerivativesSoldWeightedAverageExpectedLife" id="pfg_CreditDerivativesSoldWeightedAverageExpectedLife" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DaysDelinquentNonperforming" id="pfg_DaysDelinquentNonperforming" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DaysDelinquentValuationAllowance" id="pfg_DaysDelinquentValuationAllowance" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredIncomeTaxDisclosuresOperatingLossCarryforwardsAbstract" id="pfg_DeferredIncomeTaxDisclosuresOperatingLossCarryforwardsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredAcquisitionCostAndOtherActuarialBalancesAmortizationExpense" id="pfg_DeferredAcquisitionCostAndOtherActuarialBalancesAmortizationExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DeferredTaxLiabilitiesInvestmentIncludingDerivativeAssets" id="pfg_DeferredTaxLiabilitiesInvestmentIncludingDerivativeAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DeferredTaxLiabilitiesRealEstate" id="pfg_DeferredTaxLiabilitiesRealEstate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DefinedBenefitPlanActuarialGainLossAmortizationDisclosuresAbstract" id="pfg_DefinedBenefitPlanActuarialGainLossAmortizationDisclosuresAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesThatWillBeGranted" id="pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesThatWillBeGranted" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DefinedBenefitPlanFairValueOfPlanAssetsAbstract" id="pfg_DefinedBenefitPlanFairValueOfPlanAssetsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedBenefitPlanFinalAveragePayBenefitComputationPeriodOfEmployment" id="pfg_DefinedBenefitPlanFinalAveragePayBenefitComputationPeriodOfEmployment" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearAge65AndOver" id="pfg_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearAge65AndOver" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearUnderAge65" id="pfg_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYearUnderAge65" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DefinedBenefitPlanQualifiedPensionPlanActuarialGainsAndLossesAmortizationAllowanceCorridorNotUsed" id="pfg_DefinedBenefitPlanQualifiedPensionPlanActuarialGainsAndLossesAmortizationAllowanceCorridorNotUsed" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedContributionPlanContributionsByEmployer" id="pfg_DefinedContributionPlanContributionsByEmployer" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DefinedContributionPlanGeneralParticipantMember" id="pfg_DefinedContributionPlanGeneralParticipantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedContributionPlanGrandfatheredChoiceParticipantMember" id="pfg_DefinedContributionPlanGrandfatheredChoiceParticipantMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedContributionPlanParticipantTypeAxis" id="pfg_DefinedContributionPlanParticipantTypeAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedContributionPlanParticipantTypeDomain" id="pfg_DefinedContributionPlanParticipantTypeDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DerivativeAndHedgingRelatedAdjustments" id="pfg_DerivativeAndHedgingRelatedAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DerivativeCollateralPledged" id="pfg_DerivativeCollateralPledged" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="InterestRateDerivativesCashExchanged" id="pfg_InterestRateDerivativesCashExchanged" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DerivativeCollateralReceived" id="pfg_DerivativeCollateralReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DerivativeCreditExposure" id="pfg_DerivativeCreditExposure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DerivativeNetCreditExposure" id="pfg_DerivativeNetCreditExposure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DerivativeNotionalCreditExposureTable" id="pfg_DerivativeNotionalCreditExposureTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DiscountedCashFlowRealEstateMember" id="pfg_DiscountedCashFlowRealEstateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DiscountedCashFlowRealEstateDebtMember" id="pfg_DiscountedCashFlowRealEstateDebtMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DividendRestrictionPercentageOfPolicyholdersSurplus" id="pfg_DividendRestrictionPercentageOfPolicyholdersSurplus" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DividendsReceivedFromContributionsToUnconsolidatedEntities" id="pfg_DividendsReceivedFromContributionsToUnconsolidatedEntities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="EarningsPerShareCalculationSubtractAbstract" id="pfg_EarningsPerShareCalculationSubtractAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EastNorthCentralMember" id="pfg_EastNorthCentralMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EastSouthCentralMember" id="pfg_EastSouthCentralMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EmployeePurchasePriceAsPercentOfFairMarketValue" id="pfg_EmployeePurchasePriceAsPercentOfFairMarketValue" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EmployeeStockPurchasePlanSharesAvailableForIssuanceUnderPlan" id="pfg_EmployeeStockPurchasePlanSharesAvailableForIssuanceUnderPlan" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="EmployeeStockPurchasePlanWeightedAverageFairValueOfDiscount" id="pfg_EmployeeStockPurchasePlanWeightedAverageFairValueOfDiscount" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EntityParentAndSubsidiariesNotesGuarantorDomain" id="pfg_EntityParentAndSubsidiariesNotesGuarantorDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EntityShelfRegistrationDebtGuarantorDomain" id="pfg_EntityShelfRegistrationDebtGuarantorDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EquityMethodInvestmentSummarizedFinancialInformationProportionateShareOfNetIncomeLoss" id="pfg_EquityMethodInvestmentSummarizedFinancialInformationProportionateShareOfNetIncomeLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ExercisePriceRange1Member" id="pfg_ExercisePriceRange1Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ExercisePriceRange2Member" id="pfg_ExercisePriceRange2Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ExercisePriceRange3Member" id="pfg_ExercisePriceRange3Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ExercisePriceRange4Member" id="pfg_ExercisePriceRange4Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ExercisePriceRange5Member" id="pfg_ExercisePriceRange5Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ExercisePriceTotalRangeMember" id="pfg_ExercisePriceTotalRangeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersLineItems" id="pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersTable" id="pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTransfersTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" id="pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" id="pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" id="pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisNetAssetsLiabilities" id="pfg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisNetAssetsLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FairValueAssetsMeasuredOnRecurringBasisCashEquivalents" id="pfg_FairValueAssetsMeasuredOnRecurringBasisCashEquivalents" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FairValueAssetsMeasuredOnRecurringBasisOtherInvestments" id="pfg_FairValueAssetsMeasuredOnRecurringBasisOtherInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets" id="pfg_FairValueAssetsMeasuredOnRecurringBasisTotalAssetsExcludingSeparateAccountAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FairValueInputsAssetsLiabilitiesQuantitativeInformationLineItems" id="pfg_FairValueInputsAssetsLiabilitiesQuantitativeInformationLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueInputsQuantitativeInformationTable" id="pfg_FairValueInputsQuantitativeInformationTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsLevel2ToLevel3TransfersAmount" id="pfg_FairValueAssetsLevel2ToLevel3TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FairValueAssetsLevel3ToLevel2TransfersAmount" id="pfg_FairValueAssetsLevel3ToLevel2TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesPurchasesSalesIssuancesSettlementsAbstract" id="pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesPurchasesSalesIssuancesSettlementsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsRelatingToPositionsStillHeld" id="pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsRelatingToPositionsStillHeld" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitiesGainLossIncludedInEarningsRelatingToPositionsStillHeld" id="pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitiesGainLossIncludedInEarningsRelatingToPositionsStillHeld" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FairValueOptionContractualPrincipalAmountsOfAssetsForWhichFairValueOptionWasElected" id="pfg_FairValueOptionContractualPrincipalAmountsOfAssetsForWhichFairValueOptionWasElected" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FairValueOptionFairValueOfAssetsForWhichFairValueOptionWasElected" id="pfg_FairValueOptionFairValueOfAssetsForWhichFairValueOptionWasElected" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FairValueOptionFairValueOfLiabilitiesForWhichFairValueOptionWasElected" id="pfg_FairValueOptionFairValueOfLiabilitiesForWhichFairValueOptionWasElected" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="FairValueTransfersTableTextBlock" id="pfg_FairValueTransfersTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancialInstrumentsNotReportedAtValueTableTextBlock" id="pfg_FinancialInstrumentsNotReportedAtValueTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FiniteLivedIntangibleAssetsWeightedAverageRemainingExpectedLife" id="pfg_FiniteLivedIntangibleAssetsWeightedAverageRemainingExpectedLife" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FixedMaturitiesPledgedAsCollateral" id="pfg_FixedMaturitiesPledgedAsCollateral" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FixedMaturitySecuritiesLevel3ValuedUsingInternalPricingModels" id="pfg_FixedMaturitySecuritiesLevel3ValuedUsingInternalPricingModels" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="FixedMaturitySecuritiesValuedUsingInternalPricingModelsAbstract" id="pfg_FixedMaturitySecuritiesValuedUsingInternalPricingModelsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreement1998ProgramMember" id="pfg_FundingAgreement1998ProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreement2001ProgramMember" id="pfg_FundingAgreement2001ProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreement2011ProgramMember" id="pfg_FundingAgreement2011ProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreementAxis" id="pfg_FundingAgreementAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreementDomain" id="pfg_FundingAgreementDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreementLineItems" id="pfg_FundingAgreementLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreementTable" id="pfg_FundingAgreementTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreements" id="pfg_FundingAgreements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="FundingAgreementsAuthorizedAmountMaximum" id="pfg_FundingAgreementsAuthorizedAmountMaximum" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="FundingAgreementsProgramsNumber" id="pfg_FundingAgreementsProgramsNumber" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GovernmentDebtMember" id="pfg_GovernmentDebtMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GrossInvestmentIncomeLoss" id="pfg_GrossInvestmentIncomeLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="GuarantyFundsAbstract" id="pfg_GuarantyFundsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="IncomeLossFromContinuingOperationsBeforeIncomeTaxes" id="pfg_IncomeLossFromContinuingOperationsBeforeIncomeTaxes" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="IncomeTaxAuthorityLineItems" id="pfg_IncomeTaxAuthorityLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="IncomeTaxAuthorityTable" id="pfg_IncomeTaxAuthorityTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="IncreaseDecreaseInSharesOutstandingRollforward" id="pfg_IncreaseDecreaseInSharesOutstandingRollforward" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InterestRateOptionsMember" id="pfg_InterestRateOptionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InterestRateFutureMember" id="pfg_InterestRateFutureMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InternationalMember" id="pfg_InternationalMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="IntrinsicValueFromAwardsOrUnitsVested" id="pfg_IntrinsicValueFromAwardsOrUnitsVested" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="IntrinsicValueFromSharesSettled" id="pfg_IntrinsicValueFromSharesSettled" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="InvestmentsDisclosureAbstract" id="pfg_InvestmentsDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InvestmentsDisclosureTextBlock" id="pfg_InvestmentsDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InvestmentsInRealEstateMember" id="pfg_InvestmentsInRealEstateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InvestmentsOtherMember" id="pfg_InvestmentsOtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilitiesOtherFairValueDisclosure" id="pfg_LiabilitiesOtherFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LongTermDebtMinimumMaturityPeriod" id="pfg_LongTermDebtMinimumMaturityPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MarketValueAdjustmentsEmbeddedDerivatives" id="pfg_MarketValueAdjustmentsEmbeddedDerivatives" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MarketValueAdjustmentsFeeRevenues" id="pfg_MarketValueAdjustmentsFeeRevenues" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="MaximumValueOfSharesAvailableForPurchasePerYear" id="pfg_MaximumValueOfSharesAvailableForPurchasePerYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MiddleAtlanticMember" id="pfg_MiddleAtlanticMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MortgageLoansMember" id="pfg_MortgageLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MountainMember" id="pfg_MountainMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NatureOfOperationsAndSignificantAccountingPoliciesDisclosureAbstract" id="pfg_NatureOfOperationsAndSignificantAccountingPoliciesDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetRealizedCapitalGainsLossesIncomeTaxes" id="pfg_NetRealizedCapitalGainsLossesIncomeTaxes" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="NetRealizedCapitalGainsLossesMember" id="pfg_NetRealizedCapitalGainsLossesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments" id="pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstruments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsAbstract" id="pfg_NetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetUnrealizedGainsLossesDebtSecuritiesAvailableForSaleSecurities" id="pfg_NetUnrealizedGainsLossesDebtSecuritiesAvailableForSaleSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NetUnrealizedGainsLossesDerivativeInstruments" id="pfg_NetUnrealizedGainsLossesDerivativeInstruments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NewEnglandMember" id="pfg_NewEnglandMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NonperformingMember" id="pfg_NonperformingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NonrecurringFairValueMeasurementAssetsLiabilitiesAxis" id="pfg_NonrecurringFairValueMeasurementAssetsLiabilitiesAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NonrecurringFairValueMeasurementsAssetsLiabilitiesDomain" id="pfg_NonrecurringFairValueMeasurementsAssetsLiabilitiesDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable6.05PercentDue2036Member" id="pfg_NotesPayable6.05PercentDue2036Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable4.625PercentDue2042Member" id="pfg_NotesPayable4.625PercentDue2042Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable3.3PercentDue2022And4.625PercentDue2042Member" id="pfg_NotesPayable3.3PercentDue2022And4.625PercentDue2042Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable1.85PercentDue2017And3.125PercentDue2023And4.35PercentDue2043Member" id="pfg_NotesPayable1.85PercentDue2017And3.125PercentDue2023And4.35PercentDue2043Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable7.875PercentDue2014And8.875PercentDue2019Member" id="pfg_NotesPayable7.875PercentDue2014And8.875PercentDue2019Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable7.875PercentDue2014Member" id="pfg_NotesPayable7.875PercentDue2014Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable3.125PercentDue2023Member" id="pfg_NotesPayable3.125PercentDue2023Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable4.35PercentDue2043Member" id="pfg_NotesPayable4.35PercentDue2043Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization" id="pfg_OperatingExpensesIncludingDeferredAcquisitionCostsCapitalizationAndAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="OperatingExpensesMember" id="pfg_OperatingExpensesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OtherComprehensiveIncomeAvailableForSaleSecuritiesPeriodIncreaseDecreaseNetOfTax" id="pfg_OtherComprehensiveIncomeAvailableForSaleSecuritiesPeriodIncreaseDecreaseNetOfTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="OtherComprehensiveIncomeDerivativesPeriodIncreaseDecreaseNetOfTax" id="pfg_OtherComprehensiveIncomeDerivativesPeriodIncreaseDecreaseNetOfTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="OtherInvestmentTypesMember" id="pfg_OtherInvestmentTypesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OtherInvestmentsFairValueDisclosure" id="pfg_OtherInvestmentsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="OtherInvestmentsFairValueOption" id="pfg_OtherInvestmentsFairValueOption" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="OtherLiabilitiesAsDefined" id="pfg_OtherLiabilitiesAsDefined" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="OtherNonqualifiedStockOptionDisclosuresAbstract" id="pfg_OtherNonqualifiedStockOptionDisclosuresAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OtherTypesOfInvestmentsAbstract" id="pfg_OtherTypesOfInvestmentsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PacificMember" id="pfg_PacificMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ParentAndSubsidiariesNotesGuarantorAxis" id="pfg_ParentAndSubsidiariesNotesGuarantorAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ParentAndSubsidiariesShelfRegistrationDebtGuarantorAxis" id="pfg_ParentAndSubsidiariesShelfRegistrationDebtGuarantorAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ParticipatingPoliciesAsPercentageOfNumberOfLifeInsurancePoliciesInForce" id="pfg_ParticipatingPoliciesAsPercentageOfNumberOfLifeInsurancePoliciesInForce" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="PaymentsToAcquirePropertyPlantAndEquipmentNet" id="pfg_PaymentsToAcquirePropertyPlantAndEquipmentNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PercentageOfMortgageLoans" id="pfg_PercentageOfMortgageLoans" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="PerformingMember" id="pfg_PerformingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ProvisionDeferredIncomeTaxBenefitsExpense" id="pfg_ProvisionDeferredIncomeTaxBenefitsExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="QuantitativeInformationLevel3FairValueMeasurementsTableTextBlock" id="pfg_QuantitativeInformationLevel3FairValueMeasurementsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ReconciliationOfNetRealizedCapitalGainsLossesAbstract" id="pfg_ReconciliationOfNetRealizedCapitalGainsLossesAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RevenuesAndRelatedBenefitsExpensePolicyTextBlock" id="pfg_RevenuesAndRelatedBenefitsExpensePolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfAvailableForSaleSecuritiesDebtMaturitiesTableTextBlock" id="pfg_ScheduleOfAvailableForSaleSecuritiesDebtMaturitiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfBenefitObligationAssumptionsUsedTableTextBlock" id="pfg_ScheduleOfBenefitObligationAssumptionsUsedTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfChangeInMaximumFutureEarningsOfClosedBlockTableTextBlock" id="pfg_ScheduleOfChangeInMaximumFutureEarningsOfClosedBlockTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfCommercialMortgageLoansByGeographicRegionAndSpecificCollateralPropertyTypeTableTextBlock" id="pfg_ScheduleOfCommercialMortgageLoansByGeographicRegionAndSpecificCollateralPropertyTypeTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock" id="pfg_ScheduleOfCompensationRelatedCostsChargedToIncomeOrCapitalizedAsAssetTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfConsolidatedVariableInterestEntityAssetsLiabilitiesTableTextBlock" id="pfg_ScheduleOfConsolidatedVariableInterestEntityAssetsLiabilitiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfDefinedBenefitPensionPlansSupplementalInformationTableTextBlock" id="pfg_ScheduleOfDefinedBenefitPensionPlansSupplementalInformationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfExpectedAmortizationExpenseRelatedToOtherFiniteLivedIntangibleAssetsTableTextBlock" id="pfg_ScheduleOfExpectedAmortizationExpenseRelatedToOtherFiniteLivedIntangibleAssetsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfFairValueAssetsLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock" id="pfg_ScheduleOfFairValueAssetsLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfMinorityInterestsInUnconsolidatedEntitiesBalanceSheetTableTextBlock" id="pfg_ScheduleOfMinorityInterestsInUnconsolidatedEntitiesBalanceSheetTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfMinorityInterestsInUnconsolidatedEntitiesIncomeStatementTableTextBlock" id="pfg_ScheduleOfMinorityInterestsInUnconsolidatedEntitiesIncomeStatementTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfNetDeferredTaxesByJurisdictionTableTextBlock" id="pfg_ScheduleOfNetDeferredTaxesByJurisdictionTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfNetPeriodicBenefitCostAssumptionsUsedTableTextBlock" id="pfg_ScheduleOfNetPeriodicBenefitCostAssumptionsUsedTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfNetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsTableTextBlock" id="pfg_ScheduleOfNetUnrealizedGainsLossesAvailableForSaleSecuritiesAndDerivativeInstrumentsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfOtherComprehensiveIncomeLossTableTextBlock" id="pfg_ScheduleOfOtherComprehensiveIncomeLossTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfTargetAllocationOfPlanAssetsTableTextBlock" id="pfg_ScheduleOfTargetAllocationOfPlanAssetsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfUnconsolidatedVariableInterestEntityAssetsMaximumExposureTableTextBlock" id="pfg_ScheduleOfUnconsolidatedVariableInterestEntityAssetsMaximumExposureTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentCorporateMember" id="pfg_SegmentCorporateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentReportingInformationNetRealizedCapitalGainsLosses" id="pfg_SegmentReportingInformationNetRealizedCapitalGainsLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountAssetsMember" id="pfg_SeparateAccountAssetsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountLiabilitiesFairValueDisclosure" id="pfg_SeparateAccountLiabilitiesFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="SeparateAccountWithSharesOfPrincipalFinancialGroupStock" id="pfg_SeparateAccountWithSharesOfPrincipalFinancialGroupStock" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsLowerMultipleOfInitialTargetBasedOnPerformance" id="pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsLowerMultipleOfInitialTargetBasedOnPerformance" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUpperLimitMultipleOfInitialTargetBasedOnPerformance" id="pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUpperLimitMultipleOfInitialTargetBasedOnPerformance" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceGoalsInYears" id="pfg_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceGoalsInYears" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementShareBasedPaymentAwardAmountCapitalized" id="pfg_ShareBasedCompensationArrangementShareBasedPaymentAwardAmountCapitalized" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="SingleNameCreditDefaultSwapsMember" id="pfg_SingleNameCreditDefaultSwapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SouthAtlanticMember" id="pfg_SouthAtlanticMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StandardPoorsAMinusAndAboveRatingMember" id="pfg_StandardPoorsAMinusAndAboveRatingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StandardPoorsBBBPlusThruBBBMinusRatingMember" id="pfg_StandardPoorsBBBPlusThruBBBMinusRatingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StandardPoorsBBPlusThruBBMinusRatingMember" id="pfg_StandardPoorsBBPlusThruBBMinusRatingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StandardPoorsBPlusAndBelowRatingMember" id="pfg_StandardPoorsBPlusAndBelowRatingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StatutoryAccountingPracticesStatutoryNetIncomeAndSurplusAbstract" id="pfg_StatutoryAccountingPracticesStatutoryNetIncomeAndSurplusAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StatutoryInsuranceFinancialInformationDisclosureAbstract" id="pfg_StatutoryInsuranceFinancialInformationDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StatutoryInsuranceFinancialInformationDisclosureTextBlock" id="pfg_StatutoryInsuranceFinancialInformationDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StockBasedCompensationPlansMember" id="pfg_StockBasedCompensationPlansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SubsidiariesPrincipalLifeInsuranceCompanyMember" id="pfg_SubsidiariesPrincipalLifeInsuranceCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SummaryOfWeightedAverageRemainingContractualLivesForStockOptionsOutstandingAbstract" id="pfg_SummaryOfWeightedAverageRemainingContractualLivesForStockOptionsOutstandingAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TaxBenefitsRealizedFromAwardsOrUnitsPaidOut" id="pfg_TaxBenefitsRealizedFromAwardsOrUnitsPaidOut" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="TaxBenefitsRealizedFromSettlement" id="pfg_TaxBenefitsRealizedFromSettlement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="TreasuryStockAcquiredRepurchaseAuthorizationAmount" id="pfg_TreasuryStockAcquiredRepurchaseAuthorizationAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="BalancedAssetAllocationPortfoliosMember" id="pfg_BalancedAssetAllocationPortfoliosMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="UnconsolidatedVariableInterestEntityAssetsTable" id="pfg_UnconsolidatedVariableInterestEntityAssetsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="UnconsolidatedVariableInterestEntityLineItems" id="pfg_UnconsolidatedVariableInterestEntityLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="VariableInterestEntitiesDisclosureAbstract" id="pfg_VariableInterestEntitiesDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="VariableInterestEntitiesDisclosureTextBlock" id="pfg_VariableInterestEntitiesDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="WMAdvisorsMember" id="pfg_WMAdvisorsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="WestNorthCentralMember" id="pfg_WestNorthCentralMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="WestSouthCentralMember" id="pfg_WestSouthCentralMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancialInstrumentsNotReportedAtFairValueTable" id="pfg_FinancialInstrumentsNotReportedAtFairValueTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CashAndCashEquivalentFairValueDisclosure" id="pfg_CashAndCashEquivalentFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="IncreaseDecreaseInRedeemableNoncontrollingInterestRollForward" id="pfg_IncreaseDecreaseInRedeemableNoncontrollingInterestRollForward" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OtherComprehensiveIncomeLossAttributableToRedeemableNoncontrollingInterest" id="pfg_OtherComprehensiveIncomeLossAttributableToRedeemableNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="OtherComprehensiveIncomeLossNetOfTaxExcludingRedeemableNoncontrollingInterest" id="pfg_OtherComprehensiveIncomeLossNetOfTaxExcludingRedeemableNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DistributionsToRedeemableNoncontrollingInterest" id="pfg_DistributionsToRedeemableNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="InvestmentsInRealEstate" id="pfg_InvestmentsInRealEstate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ContractholderAndOtherPolicyholderFunds" id="pfg_ContractholderAndOtherPolicyholderFunds" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="OtherAssetsAsDefined" id="pfg_OtherAssetsAsDefined" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DefinedBenefitPlanYearThatRateReachesUltimateTrendRateUnderAge65" id="pfg_DefinedBenefitPlanYearThatRateReachesUltimateTrendRateUnderAge65" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedBenefitPlanYearThatRateReachesUltimateTrendRateAge65AndOver" id="pfg_DefinedBenefitPlanYearThatRateReachesUltimateTrendRateAge65AndOver" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InterestRateDerivativesPrincipalPayments" id="pfg_InterestRateDerivativesPrincipalPayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FinancialAssetTypeAxis" id="pfg_FinancialAssetTypeAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancialLiabilityTypeAxis" id="pfg_FinancialLiabilityTypeAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ReverseRepurchaseAgreementMember" id="pfg_ReverseRepurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GrossAmountRecognizedLiabilitiesSubjectToNetting" id="pfg_GrossAmountRecognizedLiabilitiesSubjectToNetting" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="GrossAmountRecognizedLiabilitiesSubjectToNettingNotOffset" id="pfg_GrossAmountRecognizedLiabilitiesSubjectToNettingNotOffset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="CollateralPledgedLiabilitiesSubjectToNettingNotOffset" id="pfg_CollateralPledgedLiabilitiesSubjectToNettingNotOffset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="NetAmountLiabilitiesSubjectToNetting" id="pfg_NetAmountLiabilitiesSubjectToNetting" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="GrossAmountRecognizedAssetsSubjectToNetting" id="pfg_GrossAmountRecognizedAssetsSubjectToNetting" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="GrossAmountRecognizedAssetsSubjectToNettingNotOffset" id="pfg_GrossAmountRecognizedAssetsSubjectToNettingNotOffset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CollateralReceivedAssetsSubjectToNettingNotOffset" id="pfg_CollateralReceivedAssetsSubjectToNettingNotOffset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NetAmountAssetsSubjectToNetting" id="pfg_NetAmountAssetsSubjectToNetting" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="PurchaseOfSubsidiarySharesFromRedeemableNoncontrollingInterest" id="pfg_PurchaseOfSubsidiarySharesFromRedeemableNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="MinorityInterestIncreaseFromContributionsFromNoncontrollingInterest" id="pfg_MinorityInterestIncreaseFromContributionsFromNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AdjustmentsToRedemptionAmountOfRedeemableNoncontrollingInterest" id="pfg_AdjustmentsToRedemptionAmountOfRedeemableNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ContributionsToRedeemableNoncontrollingInterest" id="pfg_ContributionsToRedeemableNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DeferredTaxLiabilitiesDeferredAcquisitionCosts" id="pfg_DeferredTaxLiabilitiesDeferredAcquisitionCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="StatutoryReservesAssumedByAffiliatedReinsuranceSubsidiaries" id="pfg_StatutoryReservesAssumedByAffiliatedReinsuranceSubsidiaries" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="OperatingRevenues" id="pfg_OperatingRevenues" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DividendsReceivedFromContributionsToUnconsolidatedEntitiesAbstract" id="pfg_DividendsReceivedFromContributionsToUnconsolidatedEntitiesAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RealEstateDepreciationExpense" id="pfg_RealEstateDepreciationExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="RealEstateInvestmentAccumulatedDepreciation" id="pfg_RealEstateInvestmentAccumulatedDepreciation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="StockBasedCompensationPlans2014StockIncentivePlanAmendedAndRestated2010StockIncentivePlanStockIncentivePlanMember" id="pfg_StockBasedCompensationPlans2014StockIncentivePlanAmendedAndRestated2010StockIncentivePlanStockIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OtherLimitedPartnershipAndFundInterestsMember" id="pfg_OtherLimitedPartnershipAndFundInterestsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PrincipalLifeInsuranceCompanyConsolidatedMember" id="pfg_PrincipalLifeInsuranceCompanyConsolidatedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentDepreciationAndAmortizationExpense" id="pfg_SegmentDepreciationAndAmortizationExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable3.4PercentDue2025Member" id="pfg_NotesPayable3.4PercentDue2025Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancialAssetTypeCategorizationDomain" id="pfg_FinancialAssetTypeCategorizationDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancialLiabilityTypeCategorizationDomain" id="pfg_FinancialLiabilityTypeCategorizationDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisIssuesNet" id="pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisIssuesNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AdjustmentsForAssumedChangesInAmortizationPatternsBeforeTax" id="pfg_AdjustmentsForAssumedChangesInAmortizationPatternsBeforeTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="AdjustmentsForAssumedChangesInAmortizationPatternsTax" id="pfg_AdjustmentsForAssumedChangesInAmortizationPatternsTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AdjustmentsForAssumedChangesInAmortizationPatternsNetOfTax" id="pfg_AdjustmentsForAssumedChangesInAmortizationPatternsNetOfTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsBeforeTax" id="pfg_AdjustmentsForAssumedChangesInLiabilityForPolicyholderBenefitsAndClaimsBeforeTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="EmployeeStockPurchasePlanMember" id="pfg_EmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentRetirementAndIncomeSolutionsMember" id="pfg_SegmentRetirementAndIncomeSolutionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments" id="pfg_SegmentReportingInformationPretaxNetRealizedCapitalGainsLossesNetOfAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ReconciliationOfOperatingRevenueAndProfitLossFromSegmentsToConsolidatedTable" id="pfg_ReconciliationOfOperatingRevenueAndProfitLossFromSegmentsToConsolidatedTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InvestmentContractsFairValueDisclosure" id="pfg_InvestmentContractsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="InterSegmentRevenue" id="pfg_InterSegmentRevenue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DerivativeNotionalCreditExposureLineItems" id="pfg_DerivativeNotionalCreditExposureLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancialInstrumentsNotReportedAtFairValueLineItems" id="pfg_FinancialInstrumentsNotReportedAtFairValueLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OperatingRevenueAndProfitLossFromSegmentsToConsolidatedLineItems" id="pfg_OperatingRevenueAndProfitLossFromSegmentsToConsolidatedLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentReportingInformationTaxExpenseBenefitAssociatedWithCertainAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest" id="pfg_SegmentReportingInformationTaxExpenseBenefitAssociatedWithCertainAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="EquityMethodInvestmentsRelatedAdjustments" id="pfg_EquityMethodInvestmentsRelatedAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MoneyMarketFundsAbstract" id="pfg_MoneyMarketFundsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TotalAssetsUnconsolidatedMoneyMarketMutualFund" id="pfg_TotalAssetsUnconsolidatedMoneyMarketMutualFund" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="RedeemableNoncontrollingInterestDecreaseFromDeconsolidation" id="pfg_RedeemableNoncontrollingInterestDecreaseFromDeconsolidation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable3.1PercentDue2026Member" id="pfg_NotesPayable3.1PercentDue2026Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable4.3PercentDue2046Member" id="pfg_NotesPayable4.3PercentDue2046Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ClosedBlockOperationsOperatingExpenses" id="pfg_ClosedBlockOperationsOperatingExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ShortDurationInsuranceContractsDiscountedLiabilitiesTableTextBlock" id="pfg_ShortDurationInsuranceContractsDiscountedLiabilitiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ReconciliationOfUnpaidClaimsAbstract" id="pfg_ReconciliationOfUnpaidClaimsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForClaimsOtherThanShortDuration" id="pfg_LiabilityForClaimsOtherThanShortDuration" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LongTermDisabilityGroupLifeWaiverMember" id="pfg_LongTermDisabilityGroupLifeWaiverMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GroupLifeMember" id="pfg_GroupLifeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EmployeeStockOwnershipPlanESOPEarnedAndUnearnedDeferredSharesFairValue" id="pfg_EmployeeStockOwnershipPlanESOPEarnedAndUnearnedDeferredSharesFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ValueOfAssetsReceivedInKindForPensionRiskTransferTransactions" id="pfg_ValueOfAssetsReceivedInKindForPensionRiskTransferTransactions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="NetInvestmentIncomeLossMember" id="pfg_NetInvestmentIncomeLossMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable3.1PercentDue2026AndNotesPayable4.3PercentDue2046Member" id="pfg_NotesPayable3.1PercentDue2026AndNotesPayable4.3PercentDue2046Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustmentsShortDurationInsuranceContracts" id="pfg_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustmentsShortDurationInsuranceContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ScheduleOfAccountsNotesLoansAndFinancingReceivablePurchasedAndSoldTableTextBlock" id="pfg_ScheduleOfAccountsNotesLoansAndFinancingReceivablePurchasedAndSoldTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentReportingInformationRevenueAdjustmentsRelatedToEquityMethodInvestments" id="pfg_SegmentReportingInformationRevenueAdjustmentsRelatedToEquityMethodInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="SegmentReportingInformationEarningsAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest" id="pfg_SegmentReportingInformationEarningsAdjustmentsRelatedToEquityMethodInvestmentsAndNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="StockBasedCompensation" id="pfg_StockBasedCompensation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AssetsCashAndCashEquivalentsMember" id="pfg_AssetsCashAndCashEquivalentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PlanAssetsHeldInRabbiTrusts" id="pfg_PlanAssetsHeldInRabbiTrusts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="PlanLiabilitiesHeldInRabbiTrusts" id="pfg_PlanLiabilitiesHeldInRabbiTrusts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NotesPayable6.05PercentDue2036IssuedOctober2006Member" id="pfg_NotesPayable6.05PercentDue2036IssuedOctober2006Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable6.05PercentDue2036IssuedDecember2006Member" id="pfg_NotesPayable6.05PercentDue2036IssuedDecember2006Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PooledSeparateAccountInvestmentsMember" id="pfg_PooledSeparateAccountInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SingleClientSeparateAccountInvestmentsMember" id="pfg_SingleClientSeparateAccountInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAgreementsFederalHomeLoanBankDesMoinesMember" id="pfg_FundingAgreementsFederalHomeLoanBankDesMoinesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OtherPlanAssetsMember" id="pfg_OtherPlanAssetsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SingleClientSeparateAccountsInvestedInPooledSeparateAccountMember" id="pfg_SingleClientSeparateAccountsInvestedInPooledSeparateAccountMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PercentageOfSemiAnnualPremiumOnOptionsUnexercisedPortion" id="pfg_PercentageOfSemiAnnualPremiumOnOptionsUnexercisedPortion" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PercentageOfAnnualPremiumOnOptionsUnexercisedPortion" id="pfg_PercentageOfAnnualPremiumOnOptionsUnexercisedPortion" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PreTaxOtherAdjustmentsInReconcilingSegmentRevenuesToConsolidatedIncome" id="pfg_PreTaxOtherAdjustmentsInReconcilingSegmentRevenuesToConsolidatedIncome" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="SubsegmentIndividualLifeInsuranceMember" id="pfg_SubsegmentIndividualLifeInsuranceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ProductsAndServicesEliminationsMember" id="pfg_ProductsAndServicesEliminationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CommissionIncomeMember" id="pfg_CommissionIncomeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SeniorNotesDue2028Member" id="pfg_SeniorNotesDue2028Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SeniorNotesDue2048Member" id="pfg_SeniorNotesDue2048Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredPolicyAcquisitionCostAndCapitalizedContractCostAmortizationExpense" id="pfg_DeferredPolicyAcquisitionCostAndCapitalizedContractCostAmortizationExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DeferredPolicyAcquisitionCostAndCapitalizedContractCostAdditions" id="pfg_DeferredPolicyAcquisitionCostAndCapitalizedContractCostAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ContingentFundingAgreementMember" id="pfg_ContingentFundingAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContingentFundingAgreement10YearMember" id="pfg_ContingentFundingAgreement10YearMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Delaware2028TrustMember" id="pfg_Delaware2028TrustMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContingentFundingAgreement30YearMember" id="pfg_ContingentFundingAgreement30YearMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Delaware2048TrustMember" id="pfg_Delaware2048TrustMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NumberOfContingentFundingAgreements" id="pfg_NumberOfContingentFundingAgreements" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TermOfContingentFundingAgreement" id="pfg_TermOfContingentFundingAgreement" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GuaranteesToThirdPartiesPrimarilyRelatedToFormerSubsidiariesAndJointVenturesMember" id="pfg_GuaranteesToThirdPartiesPrimarilyRelatedToFormerSubsidiariesAndJointVenturesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GuaranteesToUnconsolidatedTrustsUnderContingentFundingAgreementsMember" id="pfg_GuaranteesToUnconsolidatedTrustsUnderContingentFundingAgreementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PreCapitalizedTrustSecuritiesSold" id="pfg_PreCapitalizedTrustSecuritiesSold" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ProceedsFromPaymentsForTradingSecuritiesAndEquitySecuritiesWithOperatingIntent" id="pfg_ProceedsFromPaymentsForTradingSecuritiesAndEquitySecuritiesWithOperatingIntent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="UnrealizedGainsLossesOnEquitySecuritiesFvNiReportedInNetInvestmentIncome" id="pfg_UnrealizedGainsLossesOnEquitySecuritiesFvNiReportedInNetInvestmentIncome" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FeesAndOtherRevenuesNotWithinScopeOfRevenueRecognitionGuidance" id="pfg_FeesAndOtherRevenuesNotWithinScopeOfRevenueRecognitionGuidance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="TradingSecuritiesMember" id="pfg_TradingSecuritiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ProceedsFromSaleOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi" id="pfg_ProceedsFromSaleOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="MeasurementInputTerminalCapitalizationRateMember" id="pfg_MeasurementInputTerminalCapitalizationRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MeasurementInputLoanToValueRatioMember" id="pfg_MeasurementInputLoanToValueRatioMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MeasurementInputMarketInterestRateMember" id="pfg_MeasurementInputMarketInterestRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MeasurementInputLongDurationInterestRateMember" id="pfg_MeasurementInputLongDurationInterestRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MeasurementInputNonPerformanceRiskMember" id="pfg_MeasurementInputNonPerformanceRiskMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountAssetsMeasurementInput" id="pfg_SeparateAccountAssetsMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ProceedsFromMaturitiesRepaymentsAndCallsOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi" id="pfg_ProceedsFromMaturitiesRepaymentsAndCallsOfDebtSecuritiesAvailableForSaleAndEquitySecuritiesFvNi" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="GainLossOnInvestmentsStatementOfOperationsTableTextBlock" id="pfg_GainLossOnInvestmentsStatementOfOperationsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="VariableInterestEntityFullySecuredDebtOfInternationalRealEstateFundsIncludedInMaximumLossExposureAmount" id="pfg_VariableInterestEntityFullySecuredDebtOfInternationalRealEstateFundsIncludedInMaximumLossExposureAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="RedeemableNoncontrollingInterestChangeInShareBasedCompensation" id="pfg_RedeemableNoncontrollingInterestChangeInShareBasedCompensation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions" id="pfg_InvestmentAdvisoryAssetManagementAndInsuranceFeesAndCommissions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="UnsecuredLineOfCreditMember" id="pfg_UnsecuredLineOfCreditMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DefinedBenefitPlanEquitySecuritiesUsSmallMidCapMember" id="pfg_DefinedBenefitPlanEquitySecuritiesUsSmallMidCapMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Post65MedicalPlansMember" id="pfg_Post65MedicalPlansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredTaxLiabilitiesPolicyholderLiabilities" id="pfg_DeferredTaxLiabilitiesPolicyholderLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="OtherCorporateEquitiesMember" id="pfg_OtherCorporateEquitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetUnrealizedGainsLossesOtherInvestmentsAndNoncontrollingInterestAdjustments" id="pfg_NetUnrealizedGainsLossesOtherInvestmentsAndNoncontrollingInterestAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PeriodicSettlementOnDerivatives" id="pfg_PeriodicSettlementOnDerivatives" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="BenefitsClaimsAndSettlementExpensesMember" id="pfg_BenefitsClaimsAndSettlementExpensesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfCumulativeBasisAdjustmentsForFairValueHedgesTableTextBlock" id="pfg_ScheduleOfCumulativeBasisAdjustmentsForFairValueHedgesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfEffectOfDerivativesInFairValueAndCashFlowHedgingRelationshipsAndRelatedHedgedItemsOnConsolidatedStatementOfOperationsTableTextBlock" id="pfg_ScheduleOfEffectOfDerivativesInFairValueAndCashFlowHedgingRelationshipsAndRelatedHedgedItemsOnConsolidatedStatementOfOperationsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="HedgedAssetDiscontinuedFairValueHedge" id="pfg_HedgedAssetDiscontinuedFairValueHedge" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="HedgedAssetFairValueHedgeIncludingDiscontinued" id="pfg_HedgedAssetFairValueHedgeIncludingDiscontinued" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="HedgedAssetFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease" id="pfg_HedgedAssetFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FixedMaturitiesSecuritiesAvailableForSaleMember" id="pfg_FixedMaturitiesSecuritiesAvailableForSaleMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DisclosureOfContingenciesGuaranteesIndemnificationsAndLeasesTextBlock" id="pfg_DisclosureOfContingenciesGuaranteesIndemnificationsAndLeasesTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfLeaseLiabilityMaturityTableTextBlock" id="pfg_ScheduleOfLeaseLiabilityMaturityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseBalanceSheetDisclosureTableTextBlock" id="pfg_LeaseBalanceSheetDisclosureTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseAssetsAbstract" id="pfg_LeaseAssetsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseLiabilitiesAbstract" id="pfg_LeaseLiabilitiesAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TotalLeaseLiabilities" id="pfg_TotalLeaseLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="OtherLeaseCost" id="pfg_OtherLeaseCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LeaseLiabilitiesPaymentsRollingMaturityAbstract" id="pfg_LeaseLiabilitiesPaymentsRollingMaturityAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseLiabilityPaymentsDueInNextRollingTwelveMonths" id="pfg_LeaseLiabilityPaymentsDueInNextRollingTwelveMonths" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseLiabilityPaymentsDueInRollingYearTwo" id="pfg_LeaseLiabilityPaymentsDueInRollingYearTwo" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseLiabilityPaymentsDueInRollingYearThree" id="pfg_LeaseLiabilityPaymentsDueInRollingYearThree" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseLiabilityPaymentsDueInRollingYearFour" id="pfg_LeaseLiabilityPaymentsDueInRollingYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseLiabilityPaymentsDueInRollingYearFive" id="pfg_LeaseLiabilityPaymentsDueInRollingYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseLiabilityPaymentsDueInRollingAfterYearFive" id="pfg_LeaseLiabilityPaymentsDueInRollingAfterYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseLiabilityPaymentsDue" id="pfg_LeaseLiabilityPaymentsDue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LeaseLiabilityUndiscountedExcessAmount" id="pfg_LeaseLiabilityUndiscountedExcessAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DisclosureOfLeaseQuantitativeAbstract" id="pfg_DisclosureOfLeaseQuantitativeAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContingenciesGuaranteesIndemnificationsAndLeasesDisclosureAbstract" id="pfg_ContingenciesGuaranteesIndemnificationsAndLeasesDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TotalLeaseRightOfUseAssets" id="pfg_TotalLeaseRightOfUseAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ScheduleOfLeasesOfLesseeWeightedAverageRemainingTermAndWeightedAverageDiscountRateTableTextBlock" id="pfg_ScheduleOfLeasesOfLesseeWeightedAverageRemainingTermAndWeightedAverageDiscountRateTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable3.7PercentDue2029Member" id="pfg_NotesPayable3.7PercentDue2029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseCostFinanceLeaseAbstract" id="pfg_LeaseCostFinanceLeaseAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DerivativeFairValueOfDerivativeLiabilityInvestmentAndUniversalLifeContracts" id="pfg_DerivativeFairValueOfDerivativeLiabilityInvestmentAndUniversalLifeContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="InvestmentAndUniversalLifeContractsMember" id="pfg_InvestmentAndUniversalLifeContractsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CertainSponsoredInvestmentFunds" id="pfg_CertainSponsoredInvestmentFunds" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="VariableInterestEntityPrimaryBeneficiaryMandatoryRetirementSavingsMember" id="pfg_VariableInterestEntityPrimaryBeneficiaryMandatoryRetirementSavingsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="VariableInterestEntityPrimaryBeneficiaryRealEstateMember" id="pfg_VariableInterestEntityPrimaryBeneficiaryRealEstateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="VariableInterestEntityPrimaryBeneficiarySponsoredInvestmentFundsMember" id="pfg_VariableInterestEntityPrimaryBeneficiarySponsoredInvestmentFundsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ReinsuranceRecoverablesMember" id="pfg_ReinsuranceRecoverablesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OtherInvestmentsMeasurementInput" id="pfg_OtherInvestmentsMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncome" id="pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncome" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FairValueNetDerivativeAssetLiabilityLevel3ToLevel2TransfersAmount" id="pfg_FairValueNetDerivativeAssetLiabilityLevel3ToLevel2TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsPercentInvestmentGrade" id="pfg_DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsPercentInvestmentGrade" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsAveragePrice" id="pfg_DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsAveragePrice" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsAveragePriceLessThanTwelveMonths" id="pfg_DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsAveragePriceLessThanTwelveMonths" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsPercentInvestmentGradeLessThanTwelveMonths" id="pfg_DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsPercentInvestmentGradeLessThanTwelveMonths" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossContinuousUnrealizedLossPositionAggregateLossesOnInvestmentGradeInvestmentsLessThanTwelveMonths" id="pfg_DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossContinuousUnrealizedLossPositionAggregateLossesOnInvestmentGradeInvestmentsLessThanTwelveMonths" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsAveragePriceTwelveMonthsOrLonger" id="pfg_DebtSecuritiesAvailableForSaleSecuritiesWithoutAllowanceForCreditLossUnrealizedLossPositionsAveragePriceTwelveMonthsOrLonger" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="NotesPayable2.125PercentDue2030Member" id="pfg_NotesPayable2.125PercentDue2030Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EffectiveIncomeTaxRateReconciliationLowIncomeHousingTaxCreditAmortizationPercent" id="pfg_EffectiveIncomeTaxRateReconciliationLowIncomeHousingTaxCreditAmortizationPercent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetRealizedCapitalGainLossOnSaleOfDerivatives" id="pfg_NetRealizedCapitalGainLossOnSaleOfDerivatives" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="GainLossOnMortgageLoans" id="pfg_GainLossOnMortgageLoans" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="InterestRateForwardsMember" id="pfg_InterestRateForwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisNetDerivativeAssetsLiabilitiesGainLossIncludedInEarningsRelatingToPositionsStillHeld" id="pfg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisNetDerivativeAssetsLiabilitiesGainLossIncludedInEarningsRelatingToPositionsStillHeld" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="VariableInterestEntityPrimaryBeneficiaryResidentialMortgageLoansMember" id="pfg_VariableInterestEntityPrimaryBeneficiaryResidentialMortgageLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AociDebtSecuritiesAvailableForSaleWithAllowanceForCreditLossCumulativeGainLossPreTax" id="pfg_AociDebtSecuritiesAvailableForSaleWithAllowanceForCreditLossCumulativeGainLossPreTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="AssetCarryingValueUsedIfDistributionsReceivedInExcessOfInvestment" id="pfg_AssetCarryingValueUsedIfDistributionsReceivedInExcessOfInvestment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="StockBasedCompensationDirectorsStockPlanStockIncentivePlanAmendedAndRestatedStockIncentivePlanDirectorsStockPlanMember" id="pfg_StockBasedCompensationDirectorsStockPlanStockIncentivePlanAmendedAndRestatedStockIncentivePlanDirectorsStockPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="StockBasedCompensationPlans2021StockIncentivePlanMember" id="pfg_StockBasedCompensationPlans2021StockIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestYearSixOriginatedFiveYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestYearSixOriginatedFiveYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DefinedBenefitPlanNonqualifiedPensionPlanMarketValueOfAssetsHeldInTrust" id="pfg_DefinedBenefitPlanNonqualifiedPensionPlanMarketValueOfAssetsHeldInTrust" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="StockBasedCompensationPlans2021StockIncentivePlan2020DirectorsStockPlan2014DirectorsStockPlanAnd2005DirectorsStockPlanMember" id="pfg_StockBasedCompensationPlans2021StockIncentivePlan2020DirectorsStockPlan2014DirectorsStockPlanAnd2005DirectorsStockPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DirectAssumedPremiumsEarned" id="pfg_DirectAssumedPremiumsEarned" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderBenefitsAndClaimsDirectAssumed" id="pfg_PolicyholderBenefitsAndClaimsDirectAssumed" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="PolicyHolderBenefitsAndClaimIncurredNet" id="pfg_PolicyHolderBenefitsAndClaimIncurredNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfInterestIncomeOnNonAccrualFinancingReceivablesTableTextBlock" id="pfg_ScheduleOfInterestIncomeOnNonAccrualFinancingReceivablesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ReinsuranceRecoverableAndDepositReceivable" id="pfg_ReinsuranceRecoverableAndDepositReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ChangeInFairValueOfFundsWithheldEmbeddedDerivative" id="pfg_ChangeInFairValueOfFundsWithheldEmbeddedDerivative" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="CostOfReinsuranceAmortization" id="pfg_CostOfReinsuranceAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="FundsWithheldPayableEmbeddedDerivativeMember" id="pfg_FundsWithheldPayableEmbeddedDerivativeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfRevenuesFromExitedBusinessTableTextBlock" id="pfg_ScheduleOfRevenuesFromExitedBusinessTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RevenuesFromExitedBusinessAbstract" id="pfg_RevenuesFromExitedBusinessAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AmortizationOfReinsuranceGain" id="pfg_AmortizationOfReinsuranceGain" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="RevenueFromExitedBusiness" id="pfg_RevenueFromExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AmortizationOfReinsuranceGainLoss" id="pfg_AmortizationOfReinsuranceGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FundsHeldUnderReinsuranceAgreementsAssetTable" id="pfg_FundsHeldUnderReinsuranceAgreementsAssetTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundsHeldUnderReinsuranceAgreementsAssetLineItems" id="pfg_FundsHeldUnderReinsuranceAgreementsAssetLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundsHeldUnderReinsuranceAgreementsAssetAxis" id="pfg_FundsHeldUnderReinsuranceAgreementsAssetAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundsHeldUnderReinsuranceAgreementsAssetDomain" id="pfg_FundsHeldUnderReinsuranceAgreementsAssetDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FixedMaturitiesTradingMember" id="pfg_FixedMaturitiesTradingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AccruedInterestIncomeReceivableMember" id="pfg_AccruedInterestIncomeReceivableMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EmbeddedDerivativeAsset" id="pfg_EmbeddedDerivativeAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ScheduleOfCostOfReinsuranceAssetAndLiabilityTableTextBlock" id="pfg_ScheduleOfCostOfReinsuranceAssetAndLiabilityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfAssetsHeldInSupportOfReservesAssociatedWithCoinsuranceWithFundsWithheldAgreementTableTextBlock" id="pfg_ScheduleOfAssetsHeldInSupportOfReservesAssociatedWithCoinsuranceWithFundsWithheldAgreementTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundsWithheldEmbeddedDerivative" id="pfg_FundsWithheldEmbeddedDerivative" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="NetCededReinsuranceRecoverables" id="pfg_NetCededReinsuranceRecoverables" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="FiveLargestCededReinsurersMember" id="pfg_FiveLargestCededReinsurersMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetCededReinsuranceRecoverablesMember" id="pfg_NetCededReinsuranceRecoverablesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DerivativeLiabilityFairValueNetLiabilityIncludingNotSubjectToMasterNettingArrangementIncludingFundsWithheldEmbeddedDerivative" id="pfg_DerivativeLiabilityFairValueNetLiabilityIncludingNotSubjectToMasterNettingArrangementIncludingFundsWithheldEmbeddedDerivative" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NetOtherAssetsAndLiabilitiesMember" id="pfg_NetOtherAssetsAndLiabilitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AociLossCashFlowHedgeCumulativeGainLoss" id="pfg_AociLossCashFlowHedgeCumulativeGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ReinsuranceDepositReceivable" id="pfg_ReinsuranceDepositReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ReinsuranceRecoverablesClaimsReceivedNumbersOfLargestCededReinsurers" id="pfg_ReinsuranceRecoverablesClaimsReceivedNumbersOfLargestCededReinsurers" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="CostOfReinsuranceAsset" id="pfg_CostOfReinsuranceAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="CostOfReinsuranceLiability" id="pfg_CostOfReinsuranceLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PretaxIncomeFromExitedBusiness" id="pfg_PretaxIncomeFromExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="GainLossOnFundsWithheldAssets" id="pfg_GainLossOnFundsWithheldAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PreTaxIncomeLossFromExitedBusinessAbstract" id="pfg_PreTaxIncomeLossFromExitedBusinessAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetIncomeLossPerCommonShareAbstract" id="pfg_NetIncomeLossPerCommonShareAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableAndNetInvestmentInLeaseExcludingAccruedInterestBeforeAllowanceForCreditLoss" id="pfg_FinancingReceivableAndNetInvestmentInLeaseExcludingAccruedInterestBeforeAllowanceForCreditLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FinancingReceivableAndNetInvestmentInLeaseRecordedInvestment90DaysPastDueAndStillAccruing" id="pfg_FinancingReceivableAndNetInvestmentInLeaseRecordedInvestment90DaysPastDueAndStillAccruing" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FinancingReceivableAndNetInvestmentInLeaseRecordedInvestmentNonaccrualStatus" id="pfg_FinancingReceivableAndNetInvestmentInLeaseRecordedInvestmentNonaccrualStatus" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FinancingReceivableAndNetInvestmentInLeaseNonaccrualNoAllowance" id="pfg_FinancingReceivableAndNetInvestmentInLeaseNonaccrualNoAllowance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DirectFinancingLeaseNetInvestmentInLeaseOriginatedFiveYearsBeforeLatestFiscalYear" id="pfg_DirectFinancingLeaseNetInvestmentInLeaseOriginatedFiveYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DirectFinancingLeaseNetInvestmentInLeaseOriginatedSixOrMoreYearsBeforeLatestFiscalYear" id="pfg_DirectFinancingLeaseNetInvestmentInLeaseOriginatedSixOrMoreYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DirectFinancingLeaseInterestReceivable" id="pfg_DirectFinancingLeaseInterestReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossForeignCurrencyTranslationAdjustment" id="pfg_DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossForeignCurrencyTranslationAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MortgagesAndNotesPayableMember" id="pfg_MortgagesAndNotesPayableMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureAbstract" id="pfg_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AvailableForSaleSecurityMember" id="pfg_AvailableForSaleSecurityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtSecuritiesAvailableForSaleNetCreditRecoveriesLosses" id="pfg_DebtSecuritiesAvailableForSaleNetCreditRecoveriesLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossRollforward" id="pfg_DirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossRollforward" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossForeignCurrencyTranslation" id="pfg_DirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossForeignCurrencyTranslation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossRollforward" id="pfg_FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossRollforward" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLossExcludingAccruedInterest" id="pfg_FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLossExcludingAccruedInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossRecovery" id="pfg_FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossRecovery" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossForeignCurrencyTranslation" id="pfg_FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossForeignCurrencyTranslation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestOriginatedMoreThanSixYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanSixYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ScheduleOfIncomeTaxExpenseRelatedToExitedBusinessTableTextBlock" id="pfg_ScheduleOfIncomeTaxExpenseRelatedToExitedBusinessTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestCreditLossExpenseReversal" id="pfg_FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestCreditLossExpenseReversal" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossWriteOff" id="pfg_FinancingReceivableAndDirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestAllowanceForCreditLossWriteOff" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DefinedBenefitPlanAdditionalDisclosuresAbstract" id="pfg_DefinedBenefitPlanAdditionalDisclosuresAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EquityMethodInvestmentsNetInvestmentInUnconsolidatedEntitiesMember" id="pfg_EquityMethodInvestmentsNetInvestmentInUnconsolidatedEntitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="IncreaseDecreaseInFundsWithheldNetOfReinsuranceRecoverableAndDepositReceivable" id="pfg_IncreaseDecreaseInFundsWithheldNetOfReinsuranceRecoverableAndDepositReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AssetChangesResultingFromDeconsolidationOfResidentialWholeLoanSecuritizationsAbstract" id="pfg_AssetChangesResultingFromDeconsolidationOfResidentialWholeLoanSecuritizationsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DecreaseInMortgageLoans" id="pfg_DecreaseInMortgageLoans" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="IncreaseInFixedMaturitiesAvailableForSale" id="pfg_IncreaseInFixedMaturitiesAvailableForSale" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="UnrealizedGainsLossesOnEquitySecuritiesFvNiReportedInNetRealizedCapitalGainsLossesOnFundsWithheldAssets" id="pfg_UnrealizedGainsLossesOnEquitySecuritiesFvNiReportedInNetRealizedCapitalGainsLossesOnFundsWithheldAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AssetsDesignatedToClosedBlockReinsuranceRecoverableAndDepositReceivablesNet" id="pfg_AssetsDesignatedToClosedBlockReinsuranceRecoverableAndDepositReceivablesNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="FundsHeldUnderReinsuranceAgreementsRealizedCapitalGainsLossesOnAsset" id="pfg_FundsHeldUnderReinsuranceAgreementsRealizedCapitalGainsLossesOnAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfComponentsOfNetInvestmentIncomeOnFundsWithheldAssetsPassedToCoinsurerTableTextBlock" id="pfg_ScheduleOfComponentsOfNetInvestmentIncomeOnFundsWithheldAssetsPassedToCoinsurerTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfComponentsOfNetRealizedCapitalGainsLossesOnFundsWithheldAssetsPassedToCoinsurerTableTextBlock" id="pfg_ScheduleOfComponentsOfNetRealizedCapitalGainsLossesOnFundsWithheldAssetsPassedToCoinsurerTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CreditFacilityMaturingOctober2027Member" id="pfg_CreditFacilityMaturingOctober2027Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredTaxLiabilitiesFundsWithheldEmbeddedDerivatives" id="pfg_DeferredTaxLiabilitiesFundsWithheldEmbeddedDerivatives" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CashCollateralReceivable" id="pfg_CashCollateralReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="GrossInvestmentIncomeLossOnFundsWithheldAssets" id="pfg_GrossInvestmentIncomeLossOnFundsWithheldAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="InvestmentIncomeInvestmentExpenseOnFundsWithheldAssets" id="pfg_InvestmentIncomeInvestmentExpenseOnFundsWithheldAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="NetInvestmentIncomeOnFundsWithheldAssets" id="pfg_NetInvestmentIncomeOnFundsWithheldAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="UnrealizedGainsLossesOnDebtSecuritiesTradingReportedInNetRealizedCapitalGainsLossesOnFundsWithheldAssets" id="pfg_UnrealizedGainsLossesOnDebtSecuritiesTradingReportedInNetRealizedCapitalGainsLossesOnFundsWithheldAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PrivateInvestmentsMember" id="pfg_PrivateInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InsuranceCededOutOfUlsgReservesByAffiliatedReinsuranceSubsidiaries" id="pfg_InsuranceCededOutOfUlsgReservesByAffiliatedReinsuranceSubsidiaries" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ScheduleOfStatutoryNetIncomeLossAndStatutoryCapitalAndSurplusTableTextBlock" id="pfg_ScheduleOfStatutoryNetIncomeLossAndStatutoryCapitalAndSurplusTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FundingAdjustmentsAndOtherTransfers" id="pfg_FundingAdjustmentsAndOtherTransfers" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfPreTaxIncomeLossFromExitedBusinessTableTextBlock" id="pfg_ScheduleOfPreTaxIncomeLossFromExitedBusinessTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FiniteLivedIntangibleAssetsFullyAmortizedBalance" id="pfg_FiniteLivedIntangibleAssetsFullyAmortizedBalance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="UnrealizedGainsLossesOnFixedMaturitiesTradingStillHeadAtReportedInMarketRiskBenefitRemeasurementGainLoss" id="pfg_UnrealizedGainsLossesOnFixedMaturitiesTradingStillHeadAtReportedInMarketRiskBenefitRemeasurementGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DeferredPolicyAcquisitionCostsAndOtherActuarialBalancesDisclosureTextBlock" id="pfg_DeferredPolicyAcquisitionCostsAndOtherActuarialBalancesDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfDisaggregatedUnearnedRevenueLiabilityAndReconciliationTableTextBlock" id="pfg_ScheduleOfDisaggregatedUnearnedRevenueLiabilityAndReconciliationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LongDurationAndShortDurationInsuranceMember" id="pfg_LongDurationAndShortDurationInsuranceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="WorkplaceSavingsAndRetirementSolutionsMember" id="pfg_WorkplaceSavingsAndRetirementSolutionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PensionRiskTransferMember" id="pfg_PensionRiskTransferMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentPrincipalAssetManagementMember" id="pfg_SegmentPrincipalAssetManagementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentBenefitsAndProtectionMember" id="pfg_SegmentBenefitsAndProtectionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SubsegmentSpecialtyBenefitsMember" id="pfg_SubsegmentSpecialtyBenefitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SubsegmentLifeInsuranceMember" id="pfg_SubsegmentLifeInsuranceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NotesPayable5.5PercentDue2053Member" id="pfg_NotesPayable5.5PercentDue2053Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountOtherInvestmentsMember" id="pfg_SeparateAccountOtherInvestmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountOtherAssetsMember" id="pfg_SeparateAccountOtherAssetsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountLiabilitySurrenderWithdrawalAndBenefitPayment" id="pfg_SeparateAccountLiabilitySurrenderWithdrawalAndBenefitPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountLiabilityIncreaseDecreaseFromForeignCurrencyTranslation" id="pfg_SeparateAccountLiabilityIncreaseDecreaseFromForeignCurrencyTranslation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="SeparateAccountLiabilitySurrendersWithdrawalAndBenefitPayment" id="pfg_SeparateAccountLiabilitySurrendersWithdrawalAndBenefitPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ContractholderFundsDisclosureTextBlock" id="pfg_ContractholderFundsDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfDisaggregatedPolicyholderAccountBalanceAmountsAndReconcileTotalsToContractholderFundsTableTextBlock" id="pfg_ScheduleOfDisaggregatedPolicyholderAccountBalanceAmountsAndReconcileTotalsToContractholderFundsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SegmentReportInformationMarketRiskBenefitDerivativeSettlements" id="pfg_SegmentReportInformationMarketRiskBenefitDerivativeSettlements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ScheduleOfContractHolderFundsTable" id="pfg_ScheduleOfContractHolderFundsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContractHolderFundsLineItems" id="pfg_ContractHolderFundsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContractHolderFundsReconcilingItemsInvestmentContractsWithoutSignificantFeeRevenue" id="pfg_ContractHolderFundsReconcilingItemsInvestmentContractsWithoutSignificantFeeRevenue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ContractHolderFundsReconcilingItemsOtherBalances" id="pfg_ContractHolderFundsReconcilingItemsOtherBalances" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="CertainVariableAnnuityFees" id="pfg_CertainVariableAnnuityFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MarketValueAdjustmentOfMarketRiskBenefits" id="pfg_MarketValueAdjustmentOfMarketRiskBenefits" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MarketRiskBenefitsDisclosureTextBlock" id="pfg_MarketRiskBenefitsDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MarketRiskBenefitWeightedAverageAttainedAge" id="pfg_MarketRiskBenefitWeightedAverageAttainedAge" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MarketRiskBenefitAfterIncreaseDecreaseFromInstrumentSpecificCreditRiskTableTextBlock" id="pfg_MarketRiskBenefitAfterIncreaseDecreaseFromInstrumentSpecificCreditRiskTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GuaranteedInsuranceContractMinimumCreditRateRageAxis" id="pfg_GuaranteedInsuranceContractMinimumCreditRateRageAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GuaranteedInsuranceContractMinimumCreditRateRageDomain" id="pfg_GuaranteedInsuranceContractMinimumCreditRateRageDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InvestmentOnlyMember" id="pfg_InvestmentOnlyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="IndividualDisabilityMember" id="pfg_IndividualDisabilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForFuturePolicyBenefitDisclosureTextBlock" id="pfg_LiabilityForFuturePolicyBenefitDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ParticipatingContractsLiabilityForFuturePolicyBenefitsAndClaims" id="pfg_ParticipatingContractsLiabilityForFuturePolicyBenefitsAndClaims" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="OtherContractsLiabilityForFuturePolicyBenefitsAndClaims" id="pfg_OtherContractsLiabilityForFuturePolicyBenefitsAndClaims" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LiabilityForFuturePolicyBenefitExpectedFuturePolicyBenefitForeignCurrencyTranslationAdjustment" id="pfg_LiabilityForFuturePolicyBenefitExpectedFuturePolicyBenefitForeignCurrencyTranslationAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForFuturePolicyBenefitActuarialAssumptions" id="pfg_LiabilityForFuturePolicyBenefitActuarialAssumptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="LongTermCareInsuranceMember" id="pfg_LongTermCareInsuranceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForFuturePolicyBenefitGrossPremiumOrAssessmentAndInterestAccretionTableTextBlock" id="pfg_LiabilityForFuturePolicyBenefitGrossPremiumOrAssessmentAndInterestAccretionTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForFuturePolicyBenefitExpectedUndiscountedFutureBenefitPaymentsExpectedUndiscountedFutureGrossPremiumsAndExpectedDiscountedFutureGrossPremiumsTableTextBlock" id="pfg_LiabilityForFuturePolicyBenefitExpectedUndiscountedFutureBenefitPaymentsExpectedUndiscountedFutureGrossPremiumsAndExpectedDiscountedFutureGrossPremiumsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForFuturePolicyBenefitWeightedAverageRatesOfInterestAccretionAndCurrentDiscountTableTextBlock" id="pfg_LiabilityForFuturePolicyBenefitWeightedAverageRatesOfInterestAccretionAndCurrentDiscountTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestCreditLossExpenseReversal" id="pfg_DirectFinancingLeaseNetInvestmentInLeaseExcludingAccruedInterestCreditLossExpenseReversal" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceReinsuranceImpact" id="pfg_PolicyholderAccountBalanceReinsuranceImpact" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="PolicyholderFundsAfterReinsurance" id="pfg_PolicyholderFundsAfterReinsurance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0051To0100Member" id="pfg_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0051To0100Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0101To0200Member" id="pfg_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0101To0200Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0201AndGreaterMember" id="pfg_PolicyholderAccountBalanceAboveGuaranteedMinimumCreditingRateRangeFrom0201AndGreaterMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeUpTo0100Member" id="pfg_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeUpTo0100Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0101To0200Member" id="pfg_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0101To0200Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0201To0300Member" id="pfg_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0201To0300Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0301To0400Member" id="pfg_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0301To0400Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0401AndGreaterMember" id="pfg_PolicyholderAccountBalanceGuaranteedMinimumCreditingRateRangeFrom0401AndGreaterMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PolicyholderFundsWithGuaranteedMinimumCreditingRate" id="pfg_PolicyholderFundsWithGuaranteedMinimumCreditingRate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PolicyholderFundsWithoutGuaranteedMinimumCreditingRate" id="pfg_PolicyholderFundsWithoutGuaranteedMinimumCreditingRate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LiabilityForFuturePolicyBenefitsRemeasurementGainLossDirect" id="pfg_LiabilityForFuturePolicyBenefitsRemeasurementGainLossDirect" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForFuturePolicyBenefitsRemeasurementGainLossCeded" id="pfg_LiabilityForFuturePolicyBenefitsRemeasurementGainLossCeded" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="TransferToFromSeparateAccountBalanceToFromGeneralAccount" id="pfg_TransferToFromSeparateAccountBalanceToFromGeneralAccount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="SignificantChangesToInputsAndAssumptionsThatImpactedChangeInMarketRiskBenefitsFairValueMeasurementTableTextBlock" id="pfg_SignificantChangesToInputsAndAssumptionsThatImpactedChangeInMarketRiskBenefitsFairValueMeasurementTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ReinsuranceRecoverableLiability" id="pfg_ReinsuranceRecoverableLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="UnearnedRevenueLiabilityActivityTableTextBlock" id="pfg_UnearnedRevenueLiabilityActivityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PreTaxNetRealizedCapitalGainsLossesAsAdjustedFromExitedBusinessTableTextBlock" id="pfg_PreTaxNetRealizedCapitalGainsLossesAsAdjustedFromExitedBusinessTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="UnearnedRevenueLiabilityDeferrals" id="pfg_UnearnedRevenueLiabilityDeferrals" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="UnearnedRevenueLiabilityRevenueRecognized" id="pfg_UnearnedRevenueLiabilityRevenueRecognized" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForFuturePolicyBenefitReinsuranceImpact" id="pfg_LiabilityForFuturePolicyBenefitReinsuranceImpact" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="GroupRetirementContractsProductMember" id="pfg_GroupRetirementContractsProductMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PensionMember" id="pfg_PensionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredPolicyAcquisitionCostsAndOtherActuarialBalancesDisclosuresAbstract" id="pfg_DeferredPolicyAcquisitionCostsAndOtherActuarialBalancesDisclosuresAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="OtherActuarialBalancesTable" id="pfg_OtherActuarialBalancesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="OtherActuarialBalancesLineItems" id="pfg_OtherActuarialBalancesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PolicyholderAccountBalanceSurrenderWithdrawalAndBenefitPayment" id="pfg_PolicyholderAccountBalanceSurrenderWithdrawalAndBenefitPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="UnearnedRevenueLiability" id="pfg_UnearnedRevenueLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="FairValueAssetsMeasuredOnRecurringBasisMarketRiskBenefitAsset" id="pfg_FairValueAssetsMeasuredOnRecurringBasisMarketRiskBenefitAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FairValueAssetsMeasuredOnRecurringBasisMarketRiskBenefitLiability" id="pfg_FairValueAssetsMeasuredOnRecurringBasisMarketRiskBenefitLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="SubsegmentPrincipalAssetManagementEliminationsMember" id="pfg_SubsegmentPrincipalAssetManagementEliminationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="UnearnedRevenueLiabilityAfterReinsurance" id="pfg_UnearnedRevenueLiabilityAfterReinsurance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="UnearnedRevenueLiabilityReinsuranceImpact" id="pfg_UnearnedRevenueLiabilityReinsuranceImpact" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AdditionalLiabilityLongDurationInsuranceReinsuranceImpact" id="pfg_AdditionalLiabilityLongDurationInsuranceReinsuranceImpact" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DefinedBenefitPlanAxis" id="pfg_DefinedBenefitPlanAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DefinedBenefitPlanNameDomain" id="pfg_DefinedBenefitPlanNameDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SubsegmentBenefitsAndProtectionEliminationsMember" id="pfg_SubsegmentBenefitsAndProtectionEliminationsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DerivativeAndHedgingRelatedExpenseAdjustments" id="pfg_DerivativeAndHedgingRelatedExpenseAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="EffectiveIncomeTaxRateReconciliationForeignCurrencyInflationPercent" id="pfg_EffectiveIncomeTaxRateReconciliationForeignCurrencyInflationPercent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="FundsHeldUnderReinsuranceAgreementsNetOtherAssetLiability" id="pfg_FundsHeldUnderReinsuranceAgreementsNetOtherAssetLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="HedgedLiabilityFairValueHedgeIncludingDiscontinued" id="pfg_HedgedLiabilityFairValueHedgeIncludingDiscontinued" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="HedgedLiabilityFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease" id="pfg_HedgedLiabilityFairValueHedgeIncludingDiscontinuedCumulativeIncreaseDecrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="FinancialPositionAxis" id="pfg_FinancialPositionAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="FinancialPositionDomain" id="pfg_FinancialPositionDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AdditionalLiabilityForCertainBenefitFeaturesActuarialAssumptions" id="pfg_AdditionalLiabilityForCertainBenefitFeaturesActuarialAssumptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="FairValueNetDerivativeAssetLiabilityLevel2ToLevel3TransfersAmount" id="pfg_FairValueNetDerivativeAssetLiabilityLevel2ToLevel3TransfersAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="VariableInterestEntityPrimaryBeneficiaryAssetBackedLimitedPartnershipMember" id="pfg_VariableInterestEntityPrimaryBeneficiaryAssetBackedLimitedPartnershipMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CertainOtherLoansOfConsolidatedVariableInterestEntityMember" id="pfg_CertainOtherLoansOfConsolidatedVariableInterestEntityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncomeTaxFromExitedBusiness" id="pfg_IncomeTaxFromExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="IncreaseInFixedMaturitiesTrading" id="pfg_IncreaseInFixedMaturitiesTrading" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ClosedBlockLiabilitiesIncomeTaxesPayableCurrent" id="pfg_ClosedBlockLiabilitiesIncomeTaxesPayableCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DentalVisionShortTermDisabilityCriticalIllnessAccidentHospitalIndemnityAndPfmlMember" id="pfg_DentalVisionShortTermDisabilityCriticalIllnessAccidentHospitalIndemnityAndPfmlMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="HomeOfficeAndAgentPre65MedicalLifePlanMember" id="pfg_HomeOfficeAndAgentPre65MedicalLifePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DeferredTaxAssetsOperatingLossCarryforwardsAndCapitalLossCarryforwards" id="pfg_DeferredTaxAssetsOperatingLossCarryforwardsAndCapitalLossCarryforwards" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DeferredPolicyAcquisitionCostsExcludingShortDurationContracts" id="pfg_DeferredPolicyAcquisitionCostsExcludingShortDurationContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ShortDurationLiabilityForFuturePolicyBenefitsAndClaims" id="pfg_ShortDurationLiabilityForFuturePolicyBenefitsAndClaims" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="KennethMccullumMember" id="pfg_KennethMccullumMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncomeBeforeTaxesNetOfReinsuranceActuarialAssumptions" id="pfg_IncomeBeforeTaxesNetOfReinsuranceActuarialAssumptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="MortgageLoansAndOtherLoansAbstract" id="pfg_MortgageLoansAndOtherLoansAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="InterestRateContractsInvestmentContractsHedgedMember" id="pfg_InterestRateContractsInvestmentContractsHedgedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="InterestRateContractsFixedMaturitiesAvailableForSaleHedgedMember" id="pfg_InterestRateContractsFixedMaturitiesAvailableForSaleHedgedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SingleNameTotalReturnSwapsMember" id="pfg_SingleNameTotalReturnSwapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ForeignExchangeContractsFixedMaturitiesAvailableForSaleHedgedMember" id="pfg_ForeignExchangeContractsFixedMaturitiesAvailableForSaleHedgedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ChangeInFairValueOfFundsWithheldEmbeddedDerivativeTax" id="pfg_ChangeInFairValueOfFundsWithheldEmbeddedDerivativeTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="GainLossOnFundsWithheldAssetsTax" id="pfg_GainLossOnFundsWithheldAssetsTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AmortizationOfReinsuranceGainLossTax" id="pfg_AmortizationOfReinsuranceGainLossTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="OtherImpactsOfReinsuredBusinessPreTaxIncomeTax" id="pfg_OtherImpactsOfReinsuredBusinessPreTaxIncomeTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="SubsegmentInternationalPensionMember" id="pfg_SubsegmentInternationalPensionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="BermudaReinsurerMember" id="pfg_BermudaReinsurerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequiredIncreaseDecreaseDueToReinsuranceReportingPractices" id="pfg_StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequiredIncreaseDecreaseDueToReinsuranceReportingPractices" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="StatutoryAccountingPracticesStatutoryNetIncomeAmountIncreaseDecreaseDueToReinsuranceReportingPractices" id="pfg_StatutoryAccountingPracticesStatutoryNetIncomeAmountIncreaseDecreaseDueToReinsuranceReportingPractices" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="SubsegmentInvestmentManagementMember" id="pfg_SubsegmentInvestmentManagementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AdjustmentForRevenueFromContractWithCustomerExcludedInOperatingRevenues" id="pfg_AdjustmentForRevenueFromContractWithCustomerExcludedInOperatingRevenues" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ScheduleOfReconciliationOfExpensesFromSegmentsToConsolidatedTableTextBlock" id="pfg_ScheduleOfReconciliationOfExpensesFromSegmentsToConsolidatedTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="SegmentExpenses" id="pfg_SegmentExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="SegmentReportingInformationNetRealizedCapitalGainsLossesNetOfExpenseAdjustments" id="pfg_SegmentReportingInformationNetRealizedCapitalGainsLossesNetOfExpenseAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ExpensesFromExitedBusiness" id="pfg_ExpensesFromExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ScheduleOfExpensesFromExitedBusinessTableTextBlock" id="pfg_ScheduleOfExpensesFromExitedBusinessTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ExpensesFromExitedBusinessAbstract" id="pfg_ExpensesFromExitedBusinessAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ScheduleOfReconciliationOfPreTaxOperatingEarningsFromSegmentsToConsolidatedTableTextBlock" id="pfg_ScheduleOfReconciliationOfPreTaxOperatingEarningsFromSegmentsToConsolidatedTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="SponsoredInvestmentFundsRelatedAndOtherAdjustments" id="pfg_SponsoredInvestmentFundsRelatedAndOtherAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="NetInvestmentIncomeIncludedInOperatingRevenues" id="pfg_NetInvestmentIncomeIncludedInOperatingRevenues" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossBeforePortfolioLayerMethodBasisAdjustment" id="pfg_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossBeforePortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainBeforePortfolioLayerMethodBasisAdjustment" id="pfg_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainBeforePortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedLossBeforePortfolioLayerMethodBasisAdjustment" id="pfg_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedLossBeforePortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DebtSecuritiesAvailableForSaleAllowanceForCreditLossExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustment" id="pfg_DebtSecuritiesAvailableForSaleAllowanceForCreditLossExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DebtSecuritiesAvailableForSaleExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustment" id="pfg_DebtSecuritiesAvailableForSaleExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossPortfolioLayerMethodBasisAdjustment" id="pfg_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossPortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainPortfolioLayerMethodBasisAdjustment" id="pfg_DebtSecuritiesAvailableForSaleAccumulatedGrossUnrealizedGainPortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="PrincipalCompaniaDeSegurosDeVidaChileS.a.Member" id="pfg_PrincipalCompaniaDeSegurosDeVidaChileS.a.Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PrincipalInternationalDeChileS.a.Member" id="pfg_PrincipalInternationalDeChileS.a.Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PrincipalCreditRealEstateIncomeTrustMember" id="pfg_PrincipalCreditRealEstateIncomeTrustMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustmentYearOneOriginatedCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustmentYearOneOriginatedCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestYearTwoBeforePortfolioLayerMethodBasisAdjustmentOriginatedFiscalYearBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestYearTwoBeforePortfolioLayerMethodBasisAdjustmentOriginatedFiscalYearBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestYearThreeBeforePortfolioLayerMethodBasisAdjustmentOriginatedTwoYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestYearThreeBeforePortfolioLayerMethodBasisAdjustmentOriginatedTwoYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestYearFourBeforePortfolioLayerMethodBasisAdjustmentOriginatedThreeYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestYearFourBeforePortfolioLayerMethodBasisAdjustmentOriginatedThreeYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestYearFiveBeforePortfolioLayerMethodBasisAdjustmentOriginatedFourYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestYearFiveBeforePortfolioLayerMethodBasisAdjustmentOriginatedFourYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustmentOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustmentOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossBeforePortfolioLayerMethodBasisAdjustment" id="pfg_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossBeforePortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossPortfolioLayerMethodBasisAdjustment" id="pfg_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossPortfolioLayerMethodBasisAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="SecuredSubscriptionFacilityMember" id="pfg_SecuredSubscriptionFacilityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SecuredCreditFacilitiesMember" id="pfg_SecuredCreditFacilitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="FairValueOptionContractualPrincipalAmountsOfLiabilitiesForWhichFairValueOptionWasElected" id="pfg_FairValueOptionContractualPrincipalAmountsOfLiabilitiesForWhichFairValueOptionWasElected" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AmortizationExpensesOfReinsuranceGainsLossesExitedBusiness" id="pfg_AmortizationExpensesOfReinsuranceGainsLossesExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesUnallocatedPortfolioLayerMethodBasisAdjustmentCost" id="pfg_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesUnallocatedPortfolioLayerMethodBasisAdjustmentCost" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="SegmentReportingCompensationAndOtherSegmentItemAmount" id="pfg_SegmentReportingCompensationAndOtherSegmentItemAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestAndUnallocatedBasisAdjustmentsBeforeAllowanceForCreditLoss" id="pfg_FinancingReceivableExcludingAccruedInterestAndUnallocatedBasisAdjustmentsBeforeAllowanceForCreditLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ReconciliationOfIncomeTaxFromSegmentsToConsolidatedTableTextBlock" id="pfg_ReconciliationOfIncomeTaxFromSegmentsToConsolidatedTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="MortgageLoansOnRealEstateCommercialAndConsumerNetFairValueOption" id="pfg_MortgageLoansOnRealEstateCommercialAndConsumerNetFairValueOption" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="CapitalLossCarryForwards" id="pfg_CapitalLossCarryForwards" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DerivativeInstrumentContractAxis" id="pfg_DerivativeInstrumentContractAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DerivativeInstrumentContractDomain" id="pfg_DerivativeInstrumentContractDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="EquityContractsMember" id="pfg_EquityContractsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CreditContractsMember" id="pfg_CreditContractsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CertainOtherLoansMember" id="pfg_CertainOtherLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncomeLossFromEquityMethodInvestmentsInOperatingRevenues" id="pfg_IncomeLossFromEquityMethodInvestmentsInOperatingRevenues" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="SegmentReportingInformationNetRealizedCapitalGainsLossesExpenseAdjustments" id="pfg_SegmentReportingInformationNetRealizedCapitalGainsLossesExpenseAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RevenueFromContractsWithCustomers" id="pfg_RevenueFromContractsWithCustomers" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestYearSixBeforePortfolioLayerMethodBasisAdjustmentOriginatedFiveYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestYearSixBeforePortfolioLayerMethodBasisAdjustmentOriginatedFiveYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FinancingReceivableExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustmentOriginatedMoreThanSixYearsBeforeCurrentFiscalYear" id="pfg_FinancingReceivableExcludingAccruedInterestBeforePortfolioLayerMethodBasisAdjustmentOriginatedMoreThanSixYearsBeforeCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="NotesPayable4.111PercentDue2028Member" id="pfg_NotesPayable4.111PercentDue2028Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="Delaware2055TrustMember" id="pfg_Delaware2055TrustMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SeniorNotesDue2055Member" id="pfg_SeniorNotesDue2055Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NotesPayable5.375PercentDue2033Member" id="pfg_NotesPayable5.375PercentDue2033Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PreCapitalizedContingentFundingAgreementExerciseAbstract" id="pfg_PreCapitalizedContingentFundingAgreementExerciseAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncreaseInLongTermDebtNetOfDiscount" id="pfg_IncreaseInLongTermDebtNetOfDiscount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ChangesFromDeconsolidationOfInvestmentsAbstract" id="pfg_ChangesFromDeconsolidationOfInvestmentsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DecreaseInShortTermDebt" id="pfg_DecreaseInShortTermDebt" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DecreaseInLongTermDebt" id="pfg_DecreaseInLongTermDebt" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="OtherImpactsOfExitedBusiness" id="pfg_OtherImpactsOfExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="OtherImpactsOnExpensesOfExitedBusiness" id="pfg_OtherImpactsOnExpensesOfExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="OtherImpactsOfExitedBusinessPreTaxIncomeLoss" id="pfg_OtherImpactsOfExitedBusinessPreTaxIncomeLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingExcludingUnallocatedBasisAdjustments" id="pfg_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruingExcludingUnallocatedBasisAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="CommonStockUnderlyingStockOptionsToExtentExercisedForSharePurchasesMember" id="pfg_CommonStockUnderlyingStockOptionsToExtentExercisedForSharePurchasesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NetSharesReceivedUponVestingAfterTaxWithholdingFromRestrictedStockUnitMember" id="pfg_NetSharesReceivedUponVestingAfterTaxWithholdingFromRestrictedStockUnitMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PerformanceBasedStockUnitForTargetNumberMember" id="pfg_PerformanceBasedStockUnitForTargetNumberMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncreaseInFixedMaturitiesTradingNonCash" id="pfg_IncreaseInFixedMaturitiesTradingNonCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DecreaseInMortgageLoansNonCash" id="pfg_DecreaseInMortgageLoansNonCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="KamalBhatiaMember" id="pfg_KamalBhatiaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncomeTaxExpensesBenefitsGlobalIntangibleLowTaxedIncomeAllocatedToExitedBusiness" id="pfg_IncomeTaxExpensesBenefitsGlobalIntangibleLowTaxedIncomeAllocatedToExitedBusiness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="EffectiveIncomeTaxRateReconciliationForeignTaxEffectAmountAbstract" id="pfg_EffectiveIncomeTaxRateReconciliationForeignTaxEffectAmountAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="EffectiveIncomeTaxRateReconciliationChangeInUnrecognizedTaxBenefitsAmount" id="pfg_EffectiveIncomeTaxRateReconciliationChangeInUnrecognizedTaxBenefitsAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ScheduleOfIncomeTaxesPaidNetOfRefundsReceivedTableTextBlock" id="pfg_ScheduleOfIncomeTaxesPaidNetOfRefundsReceivedTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="NumberOfReportableSegmentsDisclosedByDefinitionFlag" id="pfg_NumberOfReportableSegmentsDisclosedByDefinitionFlag" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ParticipantsEnteredOnAndAfterJuly12019Member" id="pfg_ParticipantsEnteredOnAndAfterJuly12019Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ParticipantsEnteredBeforeJuly12019Member" id="pfg_ParticipantsEnteredBeforeJuly12019Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostFixedInterestCreditingRate" id="pfg_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostFixedInterestCreditingRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostInterestCreditingRateBasedOnIndexationOfTreasuryRate" id="pfg_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostInterestCreditingRateBasedOnIndexationOfTreasuryRate" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RetirementPlanParticipantsEntryByDateAxis" id="pfg_RetirementPlanParticipantsEntryByDateAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RetirementPlanParticipantsEntryByDateDomain" id="pfg_RetirementPlanParticipantsEntryByDateDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
</xsd:schema>
