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  <xsd:element abstract="true" id="aon_ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" name="ChangesInAccumulatedOtherComprehensiveIncomeLossRollForward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="aon_CommonStockProgramsLineItems" name="CommonStockProgramsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_CompensationandBenefitsMember" name="CompensationandBenefitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_CondensedFinancialStatementsDisclosureAbstract" name="CondensedFinancialStatementsDisclosureAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_CreditFacilityExpiringFebruary2022Member" name="CreditFacilityExpiringFebruary2022Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_CreditFacilityExpiringOctober2023Member" name="CreditFacilityExpiringOctober2023Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="aon_CustomerRelatedAndContractBasedMember" name="CustomerRelatedAndContractBasedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_DataSolutionsMember" name="DataSolutionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_DebtNumberOfCommittedCreditFacilities" name="DebtNumberOfCommittedCreditFacilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_DeferredTaxAssetsAccruedInterest" name="DeferredTaxAssetsAccruedInterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_DeferredTaxAssetsLeaseGuarantees" name="DeferredTaxAssetsLeaseGuarantees" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_DeferredTaxAssetsLeaseLiability" name="DeferredTaxAssetsLeaseLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards" name="DeferredTaxAssetsNetOperatingAndCapitalLossCarryforwardsAndTaxCreditCarryforwards" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" name="DeferredTaxLiabilitiesIntangibleAssetsAndPropertyPlantAndEquipment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_DeferredTaxLiabilitiesLeaseRightofUseAsset" name="DeferredTaxLiabilitiesLeaseRightofUseAsset" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_DeferredTaxLiabilitiesOtherAccruedExpenses" name="DeferredTaxLiabilitiesOtherAccruedExpenses" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation" name="DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationUnderlyingPriceInflation" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="aon_DefinedBenefitPlanEstimatedEmployerContributionsforCurrentFiscalYearAt35FederalTaxRate" name="DefinedBenefitPlanEstimatedEmployerContributionsforCurrentFiscalYearAt35FederalTaxRate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="aon_DefinedBenefitPlanMarketRelatedValue" name="DefinedBenefitPlanMarketRelatedValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_DefinedBenefitPlanMaximumPercentageofMedicalSupplementPlanIntoFuturePeriods" name="DefinedBenefitPlanMaximumPercentageofMedicalSupplementPlanIntoFuturePeriods" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" name="DefinedBenefitPlanNetPeriodicBenefitCostBeforeRecognizedNetGainLossDuetoSettlementsandCurtailments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="aon_DefinedBenefitPlanPercentageOfTotalPensionObligations" name="DefinedBenefitPlanPercentageOfTotalPensionObligations" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="aon_DefinedBenefitPlanPercentageofMedicalSupplementPlan" name="DefinedBenefitPlanPercentageofMedicalSupplementPlan" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_DisposalGroupIncludingDiscontinuedOperationConsiderationBeforeAdjustment" name="DisposalGroupIncludingDiscontinuedOperationConsiderationBeforeAdjustment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
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  <xsd:element id="aon_DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpense" name="DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
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  <xsd:element id="aon_DisposalGroupIncludingDiscontinuedOperationsDepreciation" name="DisposalGroupIncludingDiscontinuedOperationsDepreciation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="aon_DistributableReservesAvailableAmount" name="DistributableReservesAvailableAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="aon_EliminationsAndReconcilingItemsMember" name="EliminationsAndReconcilingItemsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element id="aon_EquityOtherComprehensiveIncomeLossFromSubsidiaries" name="EquityOtherComprehensiveIncomeLossFromSubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_EuropeMiddleEastAndAfricaMember" name="EuropeMiddleEastAndAfricaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element id="aon_FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeRemainderOfFiscalYear" name="FinanceAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeRemainderOfFiscalYear" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
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  <xsd:element id="aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" name="FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" name="FinancingAndOperatingLeaseLiabilityNetOfSubleaseIncomeUndiscountedExcessAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" name="FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
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  <xsd:element id="aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" name="FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearThree" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" name="FinancingAndOperatingLeaseLiabilityPaymentsNetOfSubleaseIncomeDueYearTwo" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
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  <xsd:element abstract="true" id="aon_FixedIncomeInvestmentsPooledFundsMember" name="FixedIncomeInvestmentsPooledFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_FourPointSevenFivePercentSeniorNotesDueTwentyFortyFiveMember" name="FourPointSevenFivePercentSeniorNotesDueTwentyFortyFiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_FurnitureFixturesAndEquipmentMember" name="FurnitureFixturesAndEquipmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_GainLossOnSaleofBusinessAndInvestmentsNet" name="GainLossOnSaleofBusinessAndInvestmentsNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_GovernmentAndAgencyBondsMember" name="GovernmentAndAgencyBondsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="aon_GuaranteeOfRegisteredSecuritiesAbstract" name="GuaranteeOfRegisteredSecuritiesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
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  <xsd:element id="aon_IncomeLossBeforeEquityEarningsOfSubsidiaries" name="IncomeLossBeforeEquityEarningsOfSubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="aon_IncomeLossFromContinuingOperationsBeforeIncomeTaxes" name="IncomeLossFromContinuingOperationsBeforeIncomeTaxes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
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  <xsd:element id="aon_IncomeLossfromDiscontinuedOperationsExcludingGainLossonDisposalNetofTaxIncludingPortionAttributabletoNoncontrollingInterest" name="IncomeLossfromDiscontinuedOperationsExcludingGainLossonDisposalNetofTaxIncludingPortionAttributabletoNoncontrollingInterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
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  <xsd:element id="aon_IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" name="IncreaseDecreaseInOperatingLeaseLiabilitiesNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="aon_IntercompanyInterestExpenseIncome" name="IntercompanyInterestExpenseIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="aon_IntercompanyOtherIncomeExpenseNet" name="IntercompanyOtherIncomeExpenseNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="aon_InterestCarryforward" name="InterestCarryforward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_InvestmentsInSubsidiaries" name="InvestmentsInSubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
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  <xsd:element abstract="true" id="aon_LeadershipPerformancePlanCycle20122014Member" name="LeadershipPerformancePlanCycle20122014Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="aon_LeadershipPerformancePlanCycle20142016Member" name="LeadershipPerformancePlanCycle20142016Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_LeasesMaturityAbstract" name="LeasesMaturityAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_LesseeWeightedAverageDiscountRateAbstract" name="LesseeWeightedAverageDiscountRateAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_LesseeWeightedaverageRemainingLeaseTermAbstract" name="LesseeWeightedaverageRemainingLeaseTermAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_LyttletonPortCompanyLimitedMember" name="LyttletonPortCompanyLimitedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_MarketingTechnologyAndOtherMember" name="MarketingTechnologyAndOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_MaximumAverageMaturityOfForeignCurrencyDerivatives" name="MaximumAverageMaturityOfForeignCurrencyDerivatives" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_MaximumLengthOfTimeHedgedInForeignCurrencyUndesignatedHedge" name="MaximumLengthOfTimeHedgedInForeignCurrencyUndesignatedHedge" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" name="MoneyMarketFundsAndOtherHighlyLiquidDebtSecuritiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_NoncashLeaseActivitiesAbstract" name="NoncashLeaseActivitiesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_Noncashpaymentoflongtermdebtnet" name="Noncashpaymentoflongtermdebtnet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_NoncurrentLeaseLiabilitiesAbstract" name="NoncurrentLeaseLiabilitiesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_NotesDue2042At4250PercentMember" name="NotesDue2042At4250PercentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_NotesDueat2043at4.45PercentMember" name="NotesDueat2043at4.45PercentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_NumberOfCommercialAgreements" name="NumberOfCommercialAgreements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_NumberOfDispositions" name="NumberOfDispositions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_NumberOfPerformanceMetricsMeasured" name="NumberOfPerformanceMetricsMeasured" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_NumberofRevenueLines" name="NumberofRevenueLines" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_OperatingAndFinanceLeaseLiability" name="OperatingAndFinanceLeaseLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeaseAndFinanceLeaseLiabilityCurrent" name="OperatingLeaseAndFinanceLeaseLiabilityCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeaseAndFinanceLeaseRightofUseAsset" name="OperatingLeaseAndFinanceLeaseRightofUseAsset" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeaseFutureMinimumPaymentsDueFutureMinimumSubleaseRentalPaymentsAfterYearFive" name="OperatingLeaseFutureMinimumPaymentsDueFutureMinimumSubleaseRentalPaymentsAfterYearFive" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeaseFutureMinimumPaymentsDueFutureMinimumSubleaseRentals" name="OperatingLeaseFutureMinimumPaymentsDueFutureMinimumSubleaseRentals" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeaseFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsYearFour" name="OperatingLeaseFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsYearFour" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeaseFutureMinimumPaymentsDueNetOfSubleaseIncomeNextTwelveMonths" name="OperatingLeaseFutureMinimumPaymentsDueNetOfSubleaseIncomeNextTwelveMonths" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="aon_OperatingLeasePaymentsNetOfSubleaseRentalIncomeAbstract" name="OperatingLeasePaymentsNetOfSubleaseRentalIncomeAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_OperatingLeaseRightOfUseAssetAmortization" name="OperatingLeaseRightOfUseAssetAmortization" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_OperatingLeaseRightOfUseAssetsMember" name="OperatingLeaseRightOfUseAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsYearFive" name="OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsYearFive" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsYearTwo" name="OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentalsYearTwo" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsDueFutureSubleaseRentalsNextTwelveMonths" name="OperatingLeasesFutureMinimumPaymentsDueFutureSubleaseRentalsNextTwelveMonths" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsDueFutureSubleaseRentalsYearThree" name="OperatingLeasesFutureMinimumPaymentsDueFutureSubleaseRentalsYearThree" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentals" name="OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentals" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueAfterYearFive" name="OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueAfterYearFive" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInFiveYears" name="OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInFiveYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInFourYears" name="OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInFourYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInThreeYears" name="OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInThreeYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="aon_OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInTwoYears" name="OperatingLeasesFutureMinimumPaymentsNetOfSubleaseRentalsDueInTwoYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="aon_OrdinaryShareProgramsTable" name="OrdinaryShareProgramsTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_OtherCountryMember" name="OtherCountryMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_OtherFinancialDataAbstract" name="OtherFinancialDataAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_OtherGeneralExpenses" name="OtherGeneralExpenses" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_OtherGeneralExpensesMember" name="OtherGeneralExpensesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_OtherNoncurrentOperatingLeaseLiabilitiesMember" name="OtherNoncurrentOperatingLeaseLiabilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_OtherTaxAssetsCurrent" name="OtherTaxAssetsCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="aon_PCAdvisoryMember" name="PCAdvisoryMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_PaymentsForProceedsFromMarketableSecurities" name="PaymentsForProceedsFromMarketableSecurities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_PilkingtonNorthAmericaInc.Member" name="PilkingtonNorthAmericaInc.Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_PotentialClaimforPensionAdvisoryServicesMember" name="PotentialClaimforPensionAdvisoryServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization" name="PropertyPlantAndEquipmentAndOperatingLeaseRightOfUseAssetAfterAccumulatedDepreciationandAmortization" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="aon_RealEstateAndRealEstateInvestmentTrustMember" name="RealEstateAndRealEstateInvestmentTrustMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_RealEstateRealizationCostsMember" name="RealEstateRealizationCostsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_ReinsuranceMember" name="ReinsuranceMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_RestrictedCashOperatingFunds" name="RestrictedCashOperatingFunds" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="aon_RestructuringandRelatedCostIncurredContractTerminationCosts" name="RestructuringandRelatedCostIncurredContractTerminationCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_RetirementMember" name="RetirementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ScheduleOfCondensedComprehensiveIncomeStatementTableTextBlock" name="ScheduleOfCondensedComprehensiveIncomeStatementTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" name="ScheduleOfDeferredTaxAssetsAndLiabilitiesNettedByJurisdictionTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" name="ScheduleOfOtherPostretirementBenefitsOtherInformationTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" name="ScheduleOfPropertyPlantAndEquipmentComponentsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock" name="ScheduleofAccountsNotesLoansandFinancingReceivableAllowanceforDoubtfulAccountsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ScheduleofPerformanceBasedPlansTableTextBlock" name="ScheduleofPerformanceBasedPlansTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_SeniorNotes4.25PercentDue2042Member" name="SeniorNotes4.25PercentDue2042Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_SeniorNotes625PercentDue2040Member" name="SeniorNotes625PercentDue2040Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuable" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="aon_ShareRepurchaseProgramOf2012Member" name="ShareRepurchaseProgramOf2012Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_ShareRepurchaseProgramOf2017Member" name="ShareRepurchaseProgramOf2017Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_ShareRepurchaseProgramof2014Member" name="ShareRepurchaseProgramof2014Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" name="SharebasedCompensationArrangementbySharebasedPaymentAwardVestingConditionsPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" name="ShortTermDebtAverageOutstandingAmountWeightedAverageInterestRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_SubleaseIncomePaymentsDueAbstract" name="SubleaseIncomePaymentsDueAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_SubsidiaryGuarantorsPercentageOwned" name="SubsidiaryGuarantorsPercentageOwned" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="aon_SummaryOfSignificantAccountingPoliciesLineItems" name="SummaryOfSignificantAccountingPoliciesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_SummaryOfSignificantAccountingPoliciesTable" name="SummaryOfSignificantAccountingPoliciesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_TechnologyRationalizationMember" name="TechnologyRationalizationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_TempoBusinessMember" name="TempoBusinessMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_TheNetherlandsAndCanadaMember" name="TheNetherlandsAndCanadaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_TreasuryStockAcquiredAdditionalTransactionCosts" name="TreasuryStockAcquiredAdditionalTransactionCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="aon_TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts" name="TreasuryStockValueAcquiredCostMethodIncludingAssociatedAcquisitionCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_TrusteesOfGleedsPensionFund2016Member" name="TrusteesOfGleedsPensionFund2016Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="aon_TwoPointEightZeroPercentSeniorNotesDueTwentyTwentyOneMember" name="TwoPointEightZeroPercentSeniorNotesDueTwentyTwentyOneMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="aon_UnamortizedExpenseOnPerformanceBasedPlans" name="UnamortizedExpenseOnPerformanceBasedPlans" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
</xsd:schema>
