P95DP10DP95DP10D61000000000.02550.01380.01470.04700.01150.01290027000000000100000000520000000000.04460.00350.02380.03750.00350.02380.06370.0088751700000000false--12-31Q120190000831001falseLarge Accelerated FilerCITIGROUP INCfalse44510000000462410000001477010000001621160000000.010.0160000000006000000000309956717730996015050.97000009289000000131400000001129320000001251020000000.09900.00750.10750.00750.10300.00450.10750.00950.10750.0075400000000011000000000296000000000090000000002830000000000.11270.06760.00020.00390.00870.00870.05300.06420.00030.00340.00860.04031000000000001170000000001109000000101200000040000000009710000009860000007170000001408000000758000000936000000P9Y320300000020000000385400000020000000382290000004408800000042970000004389000000410000000044000000000.035207880000001981800000015906000000145770000001.001.00300000003000000073840071920044830000005172000000192000000625700000072800000022500000002807000000057000000731099833787133784 0000831001 2019-01-01 2019-03-31 0000831001 2019-03-31 0000831001 2018-01-01 2018-03-31 0000831001 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember 2018-12-31 0000831001 us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember 2019-03-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-03-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:RetainedEarningsMember 2018-01-01 2018-03-31 0000831001 us-gaap:RetainedEarningsMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-03-31 0000831001 us-gaap:RetainedEarningsMember 2018-12-31 0000831001 us-gaap:PreferredStockMember 2019-03-31 0000831001 us-gaap:RetainedEarningsMember 2017-12-31 0000831001 us-gaap:TreasuryStockMember 2018-01-01 2018-03-31 0000831001 us-gaap:PreferredStockMember 2018-12-31 0000831001 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2017-12-31 0000831001 us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember 2019-03-31 0000831001 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-12-31 0000831001 us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember 2019-01-01 2019-03-31 0000831001 us-gaap:NoncontrollingInterestMember 2018-03-31 0000831001 us-gaap:PreferredStockMember 2018-03-31 0000831001 us-gaap:NoncontrollingInterestMember 2018-01-01 2018-03-31 0000831001 us-gaap:NoncontrollingInterestMember 2018-12-31 0000831001 us-gaap:NoncontrollingInterestMember 2019-03-31 0000831001 us-gaap:TreasuryStockMember 2018-03-31 0000831001 us-gaap:TreasuryStockMember 2019-01-01 2019-03-31 0000831001 us-gaap:PreferredStockMember 2018-01-01 2018-03-31 0000831001 us-gaap:RetainedEarningsMember 2018-03-31 0000831001 us-gaap:NoncontrollingInterestMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember 2018-03-31 0000831001 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-03-31 0000831001 2018-03-31 0000831001 us-gaap:NoncontrollingInterestMember 2017-12-31 0000831001 us-gaap:TreasuryStockMember 2018-12-31 0000831001 us-gaap:ParentMember 2019-03-31 0000831001 c:CommonShareholdersEquityMember 2018-03-31 0000831001 us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember 2017-12-31 0000831001 us-gaap:RetainedEarningsMember 2019-03-31 0000831001 us-gaap:TreasuryStockMember 2017-12-31 0000831001 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember 2018-12-31 0000831001 us-gaap:PreferredStockMember 2019-01-01 2019-03-31 0000831001 c:CommonShareholdersEquityMember 2019-03-31 0000831001 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember 2018-01-01 2018-03-31 0000831001 us-gaap:PreferredStockMember 2017-12-31 0000831001 us-gaap:ParentMember 2018-03-31 0000831001 us-gaap:TreasuryStockMember 2019-03-31 0000831001 2017-12-31 0000831001 us-gaap:AccountingStandardsUpdate201602Member 2019-01-01 0000831001 us-gaap:AccountingStandardsUpdate201602Member us-gaap:RetainedEarningsMember 2019-01-01 0000831001 us-gaap:OperatingSegmentsMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 us-gaap:CorporateNonSegmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:OperatingSegmentsMember c:InstitutionalClientsGroupMember 2019-03-31 0000831001 us-gaap:OperatingSegmentsMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 us-gaap:CorporateNonSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:OperatingSegmentsMember c:InstitutionalClientsGroupMember 2018-12-31 0000831001 us-gaap:OperatingSegmentsMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 us-gaap:CorporateNonSegmentMember 2019-03-31 0000831001 us-gaap:OperatingSegmentsMember c:GlobalConsumerBankingMember 2018-12-31 0000831001 us-gaap:OperatingSegmentsMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 us-gaap:OperatingSegmentsMember c:GlobalConsumerBankingMember 2019-03-31 0000831001 us-gaap:CorporateNonSegmentMember 2018-12-31 0000831001 us-gaap:OperatingSegmentsMember srt:LatinAmericaMember c:CiticorpSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:OperatingSegmentsMember us-gaap:EMEAMember c:CiticorpSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:OperatingSegmentsMember srt:NorthAmericaMember c:CiticorpSegmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:OperatingSegmentsMember srt:LatinAmericaMember c:CiticorpSegmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:OperatingSegmentsMember srt:AsiaMember c:CiticorpSegmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:OperatingSegmentsMember srt:AsiaMember c:CiticorpSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:OperatingSegmentsMember srt:NorthAmericaMember c:CiticorpSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:OperatingSegmentsMember us-gaap:EMEAMember c:CiticorpSegmentMember 2019-01-01 2019-03-31 0000831001 c:CorporateFinanceMember 2019-01-01 2019-03-31 0000831001 c:LoanServicingMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:InvestmentBankingMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:InsuranceDistributionRevenueMember 2019-01-01 2019-03-31 0000831001 c:InsurancePremiumsMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:DepositRelatedFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:InsuranceDistributionRevenueMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:OtherProductsAndServicesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:CorporateFinanceMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:LoanServicingMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:OtherProductsAndServicesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:TransactionalServiceFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:InsuranceDistributionRevenueMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:TransactionalServiceFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember 2019-01-01 2019-03-31 0000831001 c:InsurancePremiumsMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:BrokerageCommissionsMember 2019-01-01 2019-03-31 0000831001 c:LoanServicingMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:InsuranceDistributionRevenueMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember 2019-01-01 2019-03-31 0000831001 c:BrokerageCommissionsMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:InsurancePremiumsMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:BrokerageCommissionsMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember 2019-01-01 2019-03-31 0000831001 c:DepositRelatedFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:InvestmentBankingMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:DepositRelatedFeesMember 2019-01-01 2019-03-31 0000831001 c:CorporateFinanceMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CorporateFinanceMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:InvestmentBankingMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:OtherProductsAndServicesMember 2019-01-01 2019-03-31 0000831001 c:DepositRelatedFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:OtherProductsAndServicesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:TransactionalServiceFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:InvestmentBankingMember 2019-01-01 2019-03-31 0000831001 c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:BrokerageCommissionsMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:InsurancePremiumsMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:TransactionalServiceFeesMember 2019-01-01 2019-03-31 0000831001 c:LoanServicingMember 2019-01-01 2019-03-31 0000831001 c:TransactionalServiceFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:TransactionalServiceFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:InsuranceDistributionRevenueMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:TransactionalServiceFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:CorporateFinanceMember 2018-01-01 2018-03-31 0000831001 c:TransactionalServiceFeesMember 2018-01-01 2018-03-31 0000831001 c:InvestmentBankingMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:OtherProductsAndServicesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:LoanServicingMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember 2018-01-01 2018-03-31 0000831001 c:BrokerageCommissionsMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:BrokerageCommissionsMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:InsurancePremiumsMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:BrokerageCommissionsMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:InsuranceDistributionRevenueMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:OtherProductsAndServicesMember 2018-01-01 2018-03-31 0000831001 c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:DepositRelatedFeesMember 2018-01-01 2018-03-31 0000831001 c:InvestmentBankingMember 2018-01-01 2018-03-31 0000831001 c:CorporateFinanceMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:DepositRelatedFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:InsuranceDistributionRevenueMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:OtherProductsAndServicesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:OtherProductsAndServicesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:InvestmentBankingMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:LoanServicingMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:InsurancePremiumsMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:CorporateFinanceMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember 2018-01-01 2018-03-31 0000831001 c:InsurancePremiumsMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:LoanServicingMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:LoanServicingMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRewardsAndPartnerPaymentsMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:InvestmentBankingMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:InsuranceDistributionRevenueMember 2018-01-01 2018-03-31 0000831001 c:BrokerageCommissionsMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:DepositRelatedFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeCardRelatedLoanFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CorporateFinanceMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:CreditAndBankCardIncomeInterchangeFeesMember 2018-01-01 2018-03-31 0000831001 c:DepositRelatedFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:InsurancePremiumsMember 2018-01-01 2018-03-31 0000831001 c:CustodyFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:GuaranteeFeesMember 2019-01-01 2019-03-31 0000831001 c:GuaranteeFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:FiduciaryFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:GuaranteeFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:GuaranteeFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CustodyFeesMember 2019-01-01 2019-03-31 0000831001 c:CustodyFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember 2019-01-01 2019-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:FiduciaryFeesMember 2019-01-01 2019-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:FiduciaryFeesMember c:GlobalConsumerBankingMember 2019-01-01 2019-03-31 0000831001 c:FiduciaryFeesMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-03-31 0000831001 c:CustodyFeesMember c:InstitutionalClientsGroupMember 2019-01-01 2019-03-31 0000831001 c:FiduciaryFeesMember 2018-01-01 2018-03-31 0000831001 c:GuaranteeFeesMember 2018-01-01 2018-03-31 0000831001 c:CustodyFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:FiduciaryFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:CustodyFeesMember 2018-01-01 2018-03-31 0000831001 c:CustodyFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember 2018-01-01 2018-03-31 0000831001 c:GuaranteeFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:FiduciaryFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:CustodyFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:GuaranteeFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:GuaranteeFeesMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-03-31 0000831001 c:AdministrationAndOtherFiduciaryFeesMember c:InstitutionalClientsGroupMember 2018-01-01 2018-03-31 0000831001 c:FiduciaryFeesMember c:GlobalConsumerBankingMember 2018-01-01 2018-03-31 0000831001 c:CommissionsAndFeesMember 2019-01-01 2019-03-31 0000831001 c:DepositRelatedFeesBankOverdraftMember 2018-01-01 2018-03-31 0000831001 c:DepositRelatedFeesBankOverdraftMember 2019-01-01 2019-03-31 0000831001 c:CommissionsAndFeesMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignExchangeContractMember 2019-01-01 2019-03-31 0000831001 us-gaap:CreditRiskContractMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignExchangeContractMember 2018-01-01 2018-03-31 0000831001 us-gaap:InterestRateContractMember 2019-01-01 2019-03-31 0000831001 c:CommodityAndOtherContractsMember 2019-01-01 2019-03-31 0000831001 us-gaap:EquityContractMember 2019-01-01 2019-03-31 0000831001 us-gaap:EquityContractMember 2018-01-01 2018-03-31 0000831001 c:CommodityAndOtherContractsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CreditRiskContractMember 2019-01-01 2019-03-31 0000831001 us-gaap:InterestRateContractMember 2018-01-01 2018-03-31 0000831001 country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000831001 srt:WeightedAverageMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000831001 country:US us-gaap:NonqualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 country:US us-gaap:QualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 srt:WeightedAverageMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 country:US us-gaap:NonqualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000831001 country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000831001 country:US us-gaap:QualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-12-31 0000831001 country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-03-31 0000831001 srt:WeightedAverageMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-03-31 0000831001 srt:WeightedAverageMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 srt:WeightedAverageMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-03-31 0000831001 country:US us-gaap:QualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:QualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 country:US us-gaap:NonqualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 country:US us-gaap:NonqualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-03-31 0000831001 country:US us-gaap:NonqualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:QualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 country:US us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-03-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 c:OtherThanSignificantPlansMeasuredAnnuallyMember country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000831001 c:OtherThanSignificantPlansMeasuredAnnuallyMember country:US us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember country:US us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 c:OtherThanSignificantPlansMeasuredAnnuallyMember us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000831001 us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000831001 c:OtherThanSignificantPlansMeasuredAnnuallyMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 c:SignificantPlansMeasuredQuarterlyMember country:US us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 country:US us-gaap:NonqualifiedPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:QualifiedPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:NonqualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:NonqualifiedPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-03-31 0000831001 country:US us-gaap:QualifiedPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:QualifiedPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 us-gaap:PostemploymentRetirementBenefitsMember 2018-01-01 2018-03-31 0000831001 us-gaap:PostemploymentRetirementBenefitsMember 2019-01-01 2019-03-31 0000831001 us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-10-01 2018-12-31 0000831001 country:US us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-10-01 2018-12-31 0000831001 us-gaap:ForeignPlanMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-10-01 2018-12-31 0000831001 country:US us-gaap:PensionPlansDefinedBenefitMember 2018-10-01 2018-12-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2019-03-31 0000831001 2018-01-01 2018-12-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2018-12-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2017-12-31 0000831001 srt:MinimumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 srt:MaximumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 srt:MaximumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000831001 srt:MinimumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-03-31 0000831001 srt:MinimumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-03-31 0000831001 srt:MaximumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-03-31 0000831001 srt:MinimumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000831001 srt:MinimumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 srt:MaximumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000831001 srt:MaximumMember us-gaap:ForeignPlanMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-03-31 0000831001 us-gaap:ScenarioForecastMember 2019-04-01 2019-12-31 0000831001 c:SeriesAAPreferredStockMember us-gaap:PreferredStockMember 2019-01-01 2019-03-31 0000831001 c:EmployeeAndDirectorsStockOptionsMember 2018-01-01 2018-03-31 0000831001 c:SeriesAAPreferredStockMember us-gaap:PreferredStockMember 2019-02-01 2019-02-28 0000831001 c:EmployeeAndDirectorsStockOptionsMember 2018-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:CorporateDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember 2018-12-31 0000831001 us-gaap:OtherDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:EquitySecuritiesMember 2018-12-31 0000831001 us-gaap:USTreasuryAndGovernmentMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember 2018-12-31 0000831001 us-gaap:EquitySecuritiesMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:USTreasuryAndGovernmentMember 2019-03-31 0000831001 us-gaap:OtherDebtSecuritiesMember 2019-03-31 0000831001 us-gaap:CorporateDebtSecuritiesMember 2019-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember 2019-03-31 0000831001 c:Maturity31to90DaysMember 2019-03-31 0000831001 us-gaap:MaturityUpTo30DaysMember 2019-03-31 0000831001 us-gaap:MaturityOver90DaysMember 2019-03-31 0000831001 us-gaap:MaturityOvernightAndOnDemandMember 2019-03-31 0000831001 us-gaap:MaturityOver90DaysMember 2018-12-31 0000831001 us-gaap:MaturityOvernightAndOnDemandMember 2018-12-31 0000831001 us-gaap:MaturityUpTo30DaysMember 2018-12-31 0000831001 c:Maturity31to90DaysMember 2018-12-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:DebtSecuritiesMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember 2018-12-31 0000831001 c:ForeignResidentialMortgageBackedSecuritiesMember 2018-12-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember 2019-03-31 0000831001 us-gaap:USTreasuryAndGovernmentMember 2019-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember 2019-03-31 0000831001 us-gaap:OtherDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:USTreasurySecuritiesMember 2019-03-31 0000831001 us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2019-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember 2018-12-31 0000831001 us-gaap:USTreasuryAndGovernmentMember 2018-12-31 0000831001 us-gaap:OtherDebtSecuritiesMember 2019-03-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2018-12-31 0000831001 c:MortgageBackedSecuritiesAltAMember 2019-03-31 0000831001 us-gaap:CorporateDebtSecuritiesMember 2019-03-31 0000831001 c:ForeignResidentialMortgageBackedSecuritiesMember 2019-03-31 0000831001 c:MortgageBackedSecuritiesAltAMember 2018-12-31 0000831001 us-gaap:USTreasurySecuritiesMember 2018-12-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:DebtSecuritiesMember 2018-12-31 0000831001 us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:CorporateDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:OtherDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:HeldtomaturitySecuritiesMember 2018-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:HeldtomaturitySecuritiesMember 2018-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:HeldtomaturitySecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:CorporateDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:HeldtomaturitySecuritiesMember 2017-12-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:HeldtomaturitySecuritiesMember 2017-12-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:AvailableforsaleSecuritiesMember 2018-03-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2017-12-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2018-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-03-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2018-03-31 0000831001 us-gaap:OtherDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:HeldtomaturitySecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:CorporateDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-03-31 0000831001 us-gaap:OtherDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000831001 us-gaap:CorporateDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2017-12-31 0000831001 c:CorporateDebtAssetBackedAndOtherDebtSecuritiesMember 2019-03-31 0000831001 c:CorporateDebtAssetBackedAndOtherDebtSecuritiesMember 2018-12-31 0000831001 us-gaap:AccountingStandardsUpdate201712Member 2018-01-01 0000831001 us-gaap:MortgageBackedSecuritiesMember 2019-03-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember 2018-03-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember us-gaap:RealEstateFundsMember 2018-12-31 0000831001 c:MutualCollectiveInvestmentFundsMember 2019-03-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember c:MutualCollectiveInvestmentFundsMember 2019-03-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember 2019-03-31 0000831001 c:MutualCollectiveInvestmentFundsMember 2018-12-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember us-gaap:HedgeFundsMember 2018-12-31 0000831001 us-gaap:PrivateEquityFundsMember 2018-12-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember us-gaap:HedgeFundsMember 2019-03-31 0000831001 us-gaap:RealEstateFundsMember 2019-03-31 0000831001 us-gaap:HedgeFundsMember 2018-12-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember c:MutualCollectiveInvestmentFundsMember 2018-12-31 0000831001 us-gaap:RealEstateFundsMember 2018-12-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember 2018-12-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember us-gaap:PrivateEquityFundsMember 2018-12-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember us-gaap:RealEstateFundsMember 2019-03-31 0000831001 us-gaap:FairValueMeasuredAtNetAssetValuePerShareMember us-gaap:PrivateEquityFundsMember 2019-03-31 0000831001 us-gaap:PrivateEquityFundsMember 2019-03-31 0000831001 us-gaap:HedgeFundsMember 2019-01-01 2019-03-31 0000831001 us-gaap:HedgeFundsMember 2019-03-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember c:MarketableEquitySecuritiesMember 2018-12-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2018-12-31 0000831001 us-gaap:PortionAtOtherThanFairValueFairValueDisclosureMember c:NonMarketableEquitySecuritiesMember 2019-03-31 0000831001 c:NonMarketableSecuritiesMeasuredUsingMeasurementAlternativeMember 2019-03-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2019-03-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember c:NonMarketableEquitySecuritiesMember 2019-03-31 0000831001 c:NonMarketableSecuritiesMeasuredUsingMeasurementAlternativeMember 2018-12-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember c:MarketableEquitySecuritiesMember 2019-03-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2018-12-31 0000831001 us-gaap:PortionAtOtherThanFairValueFairValueDisclosureMember c:NonMarketableEquitySecuritiesMember 2018-12-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2019-03-31 0000831001 us-gaap:EstimateOfFairValueFairValueDisclosureMember c:NonMarketableEquitySecuritiesMember 2018-12-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:CorporateDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:AvailableforsaleSecuritiesMember 2018-12-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2018-12-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:AvailableforsaleSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:HeldtomaturitySecuritiesMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:HeldtomaturitySecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:HeldtomaturitySecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:AvailableforsaleSecuritiesMember 2019-03-31 0000831001 us-gaap:OtherDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-03-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:HeldtomaturitySecuritiesMember 2018-12-31 0000831001 us-gaap:OtherDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:HeldtomaturitySecuritiesMember 2019-03-31 0000831001 us-gaap:OtherDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-12-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:HeldtomaturitySecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-03-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-12-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-03-31 0000831001 us-gaap:ForeignGovernmentDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-12-31 0000831001 us-gaap:CorporateDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:AvailableforsaleSecuritiesMember 2018-12-31 0000831001 us-gaap:USStatesAndPoliticalSubdivisionsMember us-gaap:HeldtomaturitySecuritiesMember 2019-03-31 0000831001 us-gaap:CorporateDebtSecuritiesMember us-gaap:AvailableforsaleSecuritiesMember 2018-12-31 0000831001 srt:MaximumMember us-gaap:HedgeFundsMember 2019-01-01 2019-03-31 0000831001 srt:MinimumMember us-gaap:HedgeFundsMember 2018-01-01 2018-12-31 0000831001 srt:MinimumMember us-gaap:HedgeFundsMember 2019-01-01 2019-03-31 0000831001 srt:MaximumMember us-gaap:HedgeFundsMember 2018-01-01 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:LTVGreaterthan100percentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:LTVGreaterthan100percentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:LtvLessThan80PercentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:Ltv80To100PercentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember c:LTVGreaterthan100percentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:Ltv80To100PercentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:LtvLessThan80PercentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:Ltv80To100PercentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:LtvLessThan80PercentMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:ContingentPrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PaymentDeferralMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PrincipalForgivenessMember 2018-01-01 2018-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-12-31 0000831001 us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-12-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-12-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-12-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-12-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-12-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2018-12-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-12-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember us-gaap:MortgagesMember 2018-12-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:LeaseFinancingMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:MortgagesMember 2019-03-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2019-03-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember us-gaap:MortgagesMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2018-12-31 0000831001 country:US us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:MortgagesMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:LeaseFinancingMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-01-01 2018-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:IndividualInstallmentAndOtherMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-01-01 2018-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:IndividualInstallmentAndOtherMember 2018-01-01 2018-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-01-01 2018-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:IndividualInstallmentAndOtherMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-12-31 0000831001 srt:NorthAmericaMember c:NewOfficeOfComptrollerOfCurrencyGuidanceMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-12-31 0000831001 srt:NorthAmericaMember c:NewOfficeOfComptrollerOfCurrencyGuidanceMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-01-01 2018-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 srt:NorthAmericaMember c:NewOfficeOfComptrollerOfCurrencyGuidanceMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-12-31 0000831001 srt:NorthAmericaMember c:NewOfficeOfComptrollerOfCurrencyGuidanceMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-01-01 2018-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember 2018-01-01 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2018-01-01 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-03-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-03-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-03-31 0000831001 c:FICOScoreGreaterThan760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-03-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-03-31 0000831001 c:FICOScore680to760Member us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-03-31 0000831001 c:FICOScoreLessthan680Member us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:LTVGreaterthan100percentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:LtvLessThan80PercentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:Ltv80To100PercentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:LtvLessThan80PercentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:Ltv80To100PercentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:LTVGreaterthan100percentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember c:LTVGreaterthan100percentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:LtvLessThan80PercentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:Ltv80To100PercentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:IndividualInstallmentAndOtherMember 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2018-01-01 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2018-01-01 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:IndividualInstallmentAndOtherMember 2018-01-01 2018-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2018-01-01 2018-12-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:PaymentDeferralMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:ContingentPrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:PrincipalForgivenessMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:GCBAndCitiHoldingsConsumerMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:CommercialMarketLoansMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:CreditCardReceivablesMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember c:InstallmentAndOtherMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-03-31 0000831001 srt:NorthAmericaMember us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 c:OutsideOfNorthAmericaMember us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:GovernmentGuaranteedCollateralMember us-gaap:ConsumerPortfolioSegmentMember c:OtherLoanMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-03-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-12-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2019-03-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-12-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2018-12-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2018-12-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2019-03-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2019-03-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:GovernmentAndOfficialInstitutionsMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-12-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2019-03-31 0000831001 country:US us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:GovernmentAndOfficialInstitutionsMember 2019-03-31 0000831001 us-gaap:NonUsMember us-gaap:CommercialPortfolioSegmentMember c:InstallmentsRevolvingCreditAndOtherMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialMarketLoansMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-01-01 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2018-01-01 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-01-01 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember 2018-01-01 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-01-01 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2018-01-01 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:ChangesInAmountOrTimingOfInterestPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:ChangesInAmountOrTimingOfPrincipalPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:ChangesInAmountOrTimingOfInterestPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:ChangesInAmountOrTimingOfPrincipalAndInterestPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:ChangesInAmountOrTimingOfPrincipalAndInterestPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:ChangesInAmountOrTimingOfPrincipalPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:ChangesInAmountOrTimingOfPrincipalPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:ChangesInAmountOrTimingOfPrincipalAndInterestPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:ChangesInAmountOrTimingOfInterestPaymentsMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:ChangesInAmountOrTimingOfPrincipalPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:ChangesInAmountOrTimingOfPrincipalPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:ChangesInAmountOrTimingOfInterestPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:ChangesInAmountOrTimingOfPrincipalPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:ChangesInAmountOrTimingOfPrincipalAndInterestPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:ChangesInAmountOrTimingOfInterestPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:ChangesInAmountOrTimingOfPrincipalAndInterestPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:ChangesInAmountOrTimingOfInterestPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:ChangesInAmountOrTimingOfPrincipalAndInterestPaymentsMember 2019-01-01 2019-03-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:PrivateBankingLoansManagedOnDelinquencyBasisMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:OthersMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:PrivateBankingLoansManagedOnDelinquencyBasisMember 2019-03-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingNonInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:ExternalCreditRatingInvestmentGradeMember us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember 2019-01-01 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LoansToFinancialInstitutionsMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:CommercialAndIndustrialMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:OthersMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember us-gaap:MortgagesMember c:FinancingReceivables30to89DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialPortfolioSegmentMember c:LeaseFinancingMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:FinancialAssetAcquiredWithCreditDeteriorationMember us-gaap:CommercialPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:FinancialAssetAcquiredWithCreditDeteriorationMember us-gaap:CommercialPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:FinancialAssetAcquiredWithCreditDeteriorationMember 2018-12-31 0000831001 us-gaap:FinancialAssetAcquiredWithCreditDeteriorationMember 2019-03-31 0000831001 us-gaap:FinancialAssetAcquiredWithCreditDeteriorationMember us-gaap:ConsumerPortfolioSegmentMember 2018-12-31 0000831001 us-gaap:FinancialAssetAcquiredWithCreditDeteriorationMember us-gaap:ConsumerPortfolioSegmentMember 2019-03-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember 2017-12-31 0000831001 us-gaap:CommercialPortfolioSegmentMember 2017-12-31 0000831001 us-gaap:ConsumerPortfolioSegmentMember 2018-03-31 0000831001 c:PurchasedCreditCardRelationshipsMember 2019-03-31 0000831001 c:OtherCustomerRelationshipsMember 2019-01-01 2019-03-31 0000831001 us-gaap:ContractBasedIntangibleAssetsMember 2019-01-01 2019-03-31 0000831001 c:OtherFiniteLivedIntangibleAssetsMember 2019-01-01 2019-03-31 0000831001 us-gaap:ContractBasedIntangibleAssetsMember 2018-12-31 0000831001 c:PresentValueOfFutureProfitsMember 2019-01-01 2019-03-31 0000831001 c:OtherCustomerRelationshipsMember 2018-12-31 0000831001 us-gaap:CoreDepositsMember 2018-12-31 0000831001 c:PurchasedCreditCardRelationshipsMember 2019-01-01 2019-03-31 0000831001 us-gaap:IndefinitelivedIntangibleAssetsMember 2019-01-01 2019-03-31 0000831001 us-gaap:IndefinitelivedIntangibleAssetsMember 2018-12-31 0000831001 us-gaap:CoreDepositsMember 2019-01-01 2019-03-31 0000831001 c:OtherFiniteLivedIntangibleAssetsMember 2019-03-31 0000831001 c:OtherFiniteLivedIntangibleAssetsMember 2018-12-31 0000831001 c:OtherCustomerRelationshipsMember 2019-03-31 0000831001 us-gaap:IndefinitelivedIntangibleAssetsMember 2019-03-31 0000831001 c:PurchasedCreditCardRelationshipsMember 2018-12-31 0000831001 us-gaap:CoreDepositsMember 2019-03-31 0000831001 c:PresentValueOfFutureProfitsMember 2018-12-31 0000831001 us-gaap:ContractBasedIntangibleAssetsMember 2019-03-31 0000831001 c:PresentValueOfFutureProfitsMember 2019-03-31 0000831001 c:AmericanAirlinesSearsTheHomeDepotCostcoandATTMember c:IntangibleAssetsExcludingMortgageServicingRightsMember us-gaap:CustomerConcentrationRiskMember us-gaap:ContractBasedIntangibleAssetsMember 2019-01-01 2019-03-31 0000831001 c:InstitutionalClientsGroupMember 2018-12-31 0000831001 us-gaap:CorporateAndOtherMember 2019-03-31 0000831001 c:GlobalConsumerBankingMember 2019-03-31 0000831001 c:GlobalConsumerBankingMember 2018-12-31 0000831001 us-gaap:CorporateAndOtherMember 2018-12-31 0000831001 c:InstitutionalClientsGroupMember 2019-03-31 0000831001 c:AmericanAirlinesSearsTheHomeDepotCostcoandATTMember c:IntangibleAssetsExcludingMortgageServicingRightsMember us-gaap:CustomerConcentrationRiskMember us-gaap:ContractBasedIntangibleAssetsMember 2018-01-01 2018-12-31 0000831001 c:CitigroupCapitalIIIMember 2019-03-31 0000831001 c:CitigroupCapitalXIIIMember 2019-03-31 0000831001 c:CitigroupCapitalXVIIIMember 2019-03-31 0000831001 c:BrokerDealerEntitiesMember 2019-03-31 0000831001 c:BankEntitiesMember 2018-12-31 0000831001 c:BankEntitiesMember 2019-03-31 0000831001 c:BrokerDealerEntitiesMember 2018-12-31 0000831001 c:BankEntitiesMember us-gaap:SeniorNotesMember 2019-03-31 0000831001 c:BankEntitiesMember us-gaap:SeniorNotesMember 2018-12-31 0000831001 srt:ParentCompanyMember 2019-03-31 0000831001 srt:ParentCompanyMember 2018-12-31 0000831001 c:CitigroupCapitalXVIIIMember us-gaap:LondonInterbankOfferedRateLIBORMember 2019-03-31 0000831001 c:CitigroupCapitalXIIIMember us-gaap:LondonInterbankOfferedRateLIBORMember 2019-03-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2018-01-01 2018-03-31 0000831001 c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:AccumulatedTranslationAdjustmentMember 2018-01-01 2018-03-31 0000831001 us-gaap:CashFlowHedgingMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2018-01-01 2018-03-31 0000831001 us-gaap:FairValueHedgingMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember 2019-01-01 2019-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:InterestRateContractMember us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2019-01-01 2019-03-31 0000831001 c:AccumulatedDefinedBenefitPlansAdjustmentFinalizationOfPlanValuationAttributableToParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AccumulatedTranslationAdjustmentMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember 2019-01-01 2019-03-31 0000831001 us-gaap:ForeignExchangeContractMember us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2018-01-01 2018-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember 2018-01-01 2018-03-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember 2018-01-01 2018-03-31 0000831001 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AccumulatedTranslationAdjustmentMember 2018-01-01 2018-03-31 0000831001 c:AccumulatedDefinedBenefitPlansAdjustmentFinalizationOfPlanValuationAttributableToParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:ForeignExchangeContractMember us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:InterestRateContractMember us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2018-03-31 0000831001 us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-01-01 2018-03-31 0000831001 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2017-12-31 0000831001 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2018-03-31 0000831001 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2017-12-31 0000831001 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2018-03-31 0000831001 us-gaap:AccumulatedTranslationAdjustmentMember 2017-12-31 0000831001 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2018-01-01 2018-03-31 0000831001 c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2017-12-31 0000831001 us-gaap:AccumulatedTranslationAdjustmentMember 2018-03-31 0000831001 us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-03-31 0000831001 us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2017-12-31 0000831001 c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2018-03-31 0000831001 us-gaap:CashFlowHedgingMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedTranslationAdjustmentMember 2019-01-01 2019-03-31 0000831001 c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2019-01-01 2019-03-31 0000831001 us-gaap:FairValueHedgingMember us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2018-12-31 0000831001 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2018-12-31 0000831001 us-gaap:AccumulatedTranslationAdjustmentMember 2018-12-31 0000831001 us-gaap:AccumulatedTranslationAdjustmentMember 2019-03-31 0000831001 c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2018-12-31 0000831001 c:AccumulatedGainLossFairValueOptionFinancialLiabilitiesAttributabletoParentMember 2019-03-31 0000831001 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2019-01-01 2019-03-31 0000831001 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2019-03-31 0000831001 us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2018-12-31 0000831001 us-gaap:AociDerivativeQualifyingAsHedgeExcludedComponentParentMember 2019-03-31 0000831001 us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember 2019-03-31 0000831001 us-gaap:CollateralizedCreditCardSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:CollateralizedCreditCardSecuritiesMember 2019-01-01 2019-03-31 0000831001 srt:WeightedAverageMember c:MortgageBackedSecuritiesWithSubordinatedInterestsIssuedByPrivateEnterprisesMember 2019-01-01 2019-03-31 0000831001 c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2019-01-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2019-01-01 2019-03-31 0000831001 srt:WeightedAverageMember c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2019-01-01 2019-03-31 0000831001 c:MortgageBackedSecuritiesWithSubordinatedInterestsIssuedByPrivateEnterprisesMember 2019-01-01 2019-03-31 0000831001 srt:WeightedAverageMember us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2019-01-01 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:CorporateLoansMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember us-gaap:CommercialRealEstateMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:HedgeFundsAndEquitiesMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:AirplanesShipsAndOtherAssetsMember 2018-12-31 0000831001 c:LoanCommitmentsMember 2019-03-31 0000831001 us-gaap:OtherThanSecuritiesInvestmentMember c:LiquidityFacilitiesMember 2018-12-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember c:LiquidityFacilitiesMember 2019-03-31 0000831001 us-gaap:OtherThanSecuritiesInvestmentMember c:LoanCommitmentsMember 2019-03-31 0000831001 c:InvestmentFundsMember c:LiquidityFacilitiesMember 2019-03-31 0000831001 c:MunicipalInvestmentsMember c:LoanCommitmentsMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:LoanCommitmentsMember 2019-03-31 0000831001 c:MunicipalInvestmentsMember c:LiquidityFacilitiesMember 2018-12-31 0000831001 us-gaap:OtherThanSecuritiesInvestmentMember c:LoanCommitmentsMember 2018-12-31 0000831001 c:MunicipalInvestmentsMember c:LoanCommitmentsMember 2018-12-31 0000831001 c:MunicipalInvestmentsMember c:LiquidityFacilitiesMember 2019-03-31 0000831001 c:LiquidityFacilitiesMember 2019-03-31 0000831001 c:LiquidityFacilitiesMember 2018-12-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember c:LoanCommitmentsMember 2018-12-31 0000831001 c:InvestmentFundsMember c:LoanCommitmentsMember 2018-12-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember c:LiquidityFacilitiesMember 2018-12-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember c:LoanCommitmentsMember 2019-03-31 0000831001 c:LoanCommitmentsMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:LiquidityFacilitiesMember 2019-03-31 0000831001 c:InvestmentFundsMember c:LiquidityFacilitiesMember 2018-12-31 0000831001 us-gaap:OtherThanSecuritiesInvestmentMember c:LiquidityFacilitiesMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:LiquidityFacilitiesMember 2018-12-31 0000831001 c:InvestmentFundsMember c:LoanCommitmentsMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:LoanCommitmentsMember 2018-12-31 0000831001 srt:WeightedAverageMember c:MortgageBackedSecuritiesWithSubordinatedInterestsIssuedByPrivateEnterprisesMember 2018-01-01 2018-03-31 0000831001 srt:WeightedAverageMember c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2018-01-01 2018-03-31 0000831001 c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2018-01-01 2018-03-31 0000831001 srt:WeightedAverageMember us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-01-01 2018-03-31 0000831001 c:MortgageBackedSecuritiesWithSubordinatedInterestsIssuedByPrivateEnterprisesMember 2018-01-01 2018-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-01-01 2018-03-31 0000831001 c:CitibankCreditCardMasterTrustMember 2018-12-31 0000831001 c:CitibankCreditCardMasterTrustMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:ResidentialMortgageBackedSecuritiesMember 2018-12-31 0000831001 us-gaap:ResidentialMortgageBackedSecuritiesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:ResidentialMortgageBackedSecuritiesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2018-12-31 0000831001 us-gaap:ResidentialMortgageBackedSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-03-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember 2019-01-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember 2018-01-01 2018-03-31 0000831001 us-gaap:CommercialMortgageBackedSecuritiesMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2019-01-01 2019-03-31 0000831001 us-gaap:ResidentialMortgageBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:ResidentialMortgageBackedSecuritiesMember 2018-01-01 2018-03-31 0000831001 c:MortgageServiceRightsMember 2018-01-01 2018-03-31 0000831001 c:MortgageServiceRightsMember 2019-01-01 2019-03-31 0000831001 c:MortgageBackedSecuritiesWithSubordinatedInterestsIssuedByPrivateEnterprisesMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-12-31 0000831001 c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2018-12-31 0000831001 c:MortgageServiceRightsMember 2018-03-31 0000831001 c:MortgageServiceRightsMember 2018-12-31 0000831001 c:MortgageServiceRightsMember 2017-12-31 0000831001 c:MortgageServiceRightsMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-03-31 0000831001 c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2019-03-31 0000831001 c:MortgageBackedSecuritiesWithSubordinatedInterestsIssuedByPrivateEnterprisesMember 2019-03-31 0000831001 c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2019-03-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2019-03-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2019-01-01 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember c:CiticorpSegmentMember 2018-01-01 2018-03-31 0000831001 c:EntityConsolidatedAdministeredAssetBackedCommercialPaperConduitMember 2019-03-31 0000831001 c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2018-01-01 2018-12-31 0000831001 srt:MaximumMember c:MunicipalSecuritiesTenderOptionBondTrustsMember 2019-01-01 2019-03-31 0000831001 c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2018-12-31 0000831001 srt:MinimumMember c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2019-01-01 2019-03-31 0000831001 c:CitibankOMNIMasterTrustMember 2019-01-01 2019-03-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2018-12-31 0000831001 srt:MaximumMember c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2019-01-01 2019-03-31 0000831001 c:EntityConsolidatedAdministeredAssetBackedCommercialPaperConduitMember 2018-12-31 0000831001 c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2019-01-01 2019-03-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember 2019-03-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember c:CiticorpSegmentMember 2018-01-01 2018-03-31 0000831001 srt:MinimumMember c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2019-03-31 0000831001 c:CitibankCreditCardMasterTrustMember 2019-01-01 2019-03-31 0000831001 c:CitibankCreditCardMasterTrustMember 2018-01-01 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember c:CiticorpSegmentMember 2019-01-01 2019-03-31 0000831001 c:CitibankOMNIMasterTrustMember 2018-01-01 2018-12-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2018-01-01 2018-03-31 0000831001 us-gaap:OtherThanSecuritiesInvestmentMember 2018-12-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2018-12-31 0000831001 c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2018-12-31 0000831001 c:ClientIntermediationMember 2018-12-31 0000831001 us-gaap:CollateralizedCreditCardSecuritiesMember 2018-12-31 0000831001 c:MunicipalInvestmentsMember 2018-12-31 0000831001 c:InvestmentFundsMember 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2018-12-31 0000831001 us-gaap:CollateralizedLoanObligationsMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember 2018-12-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember 2018-12-31 0000831001 c:ClientIntermediationMember 2019-03-31 0000831001 c:EntityAdministeredAssetBackedCommercialPaperConduitMember 2019-03-31 0000831001 c:MunicipalSecuritiesTenderOptionBondTrustsMember 2019-03-31 0000831001 us-gaap:CollateralizedCreditCardSecuritiesMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember 2019-03-31 0000831001 us-gaap:CollateralizedLoanObligationsMember 2019-03-31 0000831001 c:MortgageBackedSecuritiesIssuedByUSGovernmentCorporationsAndAgenciesMember 2019-03-31 0000831001 us-gaap:OtherThanSecuritiesInvestmentMember 2019-03-31 0000831001 c:MunicipalInvestmentsMember 2019-03-31 0000831001 c:InvestmentFundsMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember 2019-03-31 0000831001 us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2018-12-31 0000831001 us-gaap:VariableInterestEntityNotPrimaryBeneficiaryMember 2019-03-31 0000831001 c:CitibankOMNIMasterTrustMember 2019-03-31 0000831001 c:CitibankOMNIMasterTrustMember 2018-12-31 0000831001 us-gaap:AssetBackedSecuritiesMember us-gaap:CommercialRealEstateMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:AirplanesShipsAndOtherAssetsMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:CorporateLoansMember 2019-03-31 0000831001 us-gaap:AssetBackedSecuritiesMember c:HedgeFundsAndEquitiesMember 2019-03-31 0000831001 srt:WeightedAverageMember c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2018-01-01 2018-12-31 0000831001 srt:WeightedAverageMember us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-01-01 2018-12-31 0000831001 us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember 2018-01-01 2018-12-31 0000831001 c:MortgageBackedSecuritiesWithSeniorInterestsIssuedByPrivateEnterprisesMember 2018-01-01 2018-12-31 0000831001 srt:WeightedAverageMember c:MortgageBackedSecuritiesWithSubordinatedInterestsIssuedByPrivateEnterprisesMember 2018-01-01 2018-12-31 0000831001 us-gaap:CollateralizedLoanObligationsMember 2018-12-31 0000831001 us-gaap:CollateralizedLoanObligationsMember 2019-03-31 0000831001 us-gaap:MortgageBackedSecuritiesMember 2018-12-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:EquityContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember c:CommodityOptionAndOtherContractOptionsMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember c:CommodityOptionAndOtherContractOptionsMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:EquityContractMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:EquityContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:CreditRiskContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:CreditRiskContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember c:CommodityOptionAndOtherContractOptionsMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:EquityContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember c:CommodityOptionAndOtherContractOptionsMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:CreditRiskContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:CreditRiskContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:EquityContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember c:CommodityOptionAndOtherContractOptionsMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember c:CommodityOptionAndOtherContractOptionsMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:CreditRiskContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:EquityContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:EquityContractMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:InterestRateContractMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:ForeignExchangeContractMember us-gaap:NondesignatedMember us-gaap:ExchangeTradedMember 2019-03-31 0000831001 c:TradingAccountsAssetsMember us-gaap:EquityContractMember us-gaap:NondesignatedMember us-gaap:ExchangeClearedMember 2019-03-31 0000831001 c:TradingAccountsLiabilitiesMember us-gaap:CreditRiskContractMember us-gaap:NondesignatedMember us-gaap:OverTheCounterMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2018-12-31 0000831001 us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 c:CommodityAndOtherContractsMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 us-gaap:ForeignExchangeOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2018-12-31 0000831001 us-gaap:StockOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ShortMember 2018-12-31 0000831001 us-gaap:CurrencySwapMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:ShortMember 2018-12-31 0000831001 us-gaap:InterestRateContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 c:InterestRateOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2018-12-31 0000831001 us-gaap:EquityContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 c:CommodityandOtherFuturesandForwardsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 us-gaap:InterestRateContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 c:CommodityAndOtherContractsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 us-gaap:ForeignExchangeOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2019-03-31 0000831001 us-gaap:StockOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2019-03-31 0000831001 us-gaap:EquitySwapMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 us-gaap:ForeignExchangeContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 us-gaap:ForeignExchangeOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ShortMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 us-gaap:EquityContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 c:CommodityAndOtherContractsMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 us-gaap:InterestRateSwapMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 c:CommodityOptionAndOtherContractOptionsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2018-12-31 0000831001 us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 c:EquityFutureandForwardMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 c:CommodityOptionAndOtherContractOptionsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2019-03-31 0000831001 c:CommodityOptionAndOtherContractOptionsMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2019-03-31 0000831001 c:CommodityandOtherSwapsMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 c:ForeignExchangeFutureForwardandSpotMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 c:ForeignExchangeFutureForwardandSpotMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 c:InterestRateFutureandForwardMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 c:CommodityOptionAndOtherContractOptionsMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2018-12-31 0000831001 c:InterestRateOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:ShortMember 2018-12-31 0000831001 c:ForeignExchangeFutureForwardandSpotMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:ShortMember 2019-03-31 0000831001 us-gaap:ForeignExchangeContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:CommodityandOtherFuturesandForwardsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 us-gaap:ForeignExchangeOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2019-03-31 0000831001 us-gaap:StockOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2018-12-31 0000831001 us-gaap:StockOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ShortMember 2019-03-31 0000831001 c:InterestRateOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:ShortMember 2019-03-31 0000831001 c:CommodityandOtherFuturesandForwardsMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 us-gaap:InterestRateSwapMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:InterestRateOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ShortMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2019-03-31 0000831001 us-gaap:StockOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2019-03-31 0000831001 c:CommodityandOtherSwapsMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 us-gaap:EquityContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 us-gaap:CurrencySwapMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:CommodityOptionAndOtherContractOptionsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:ShortMember 2018-12-31 0000831001 c:ForeignExchangeFutureForwardandSpotMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 us-gaap:InterestRateSwapMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2018-12-31 0000831001 c:InterestRateOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2018-12-31 0000831001 us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 us-gaap:CurrencySwapMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 c:CommodityOptionAndOtherContractOptionsMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ShortMember 2018-12-31 0000831001 c:CommodityandOtherSwapsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 c:InterestRateOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 us-gaap:EquitySwapMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 c:InterestRateFutureandForwardMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 us-gaap:EquitySwapMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 c:InterestRateFutureandForwardMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ShortMember 2018-12-31 0000831001 c:EquityFutureandForwardMember us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 c:EquityFutureandForwardMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2018-12-31 0000831001 us-gaap:StockOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:LongMember 2018-12-31 0000831001 us-gaap:InterestRateSwapMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember 2019-03-31 0000831001 us-gaap:DesignatedAsHedgingInstrumentMember 2018-12-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:LongMember 2019-03-31 0000831001 us-gaap:InterestRateContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 c:CommodityOptionAndOtherContractOptionsMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:ShortMember 2019-03-31 0000831001 c:InterestRateOptionMember us-gaap:DesignatedAsHedgingInstrumentMember us-gaap:ShortMember 2018-12-31 0000831001 us-gaap:ForeignExchangeOptionMember us-gaap:NotDesignatedAsHedgingInstrumentTradingMember us-gaap:ShortMember 2018-12-31 0000831001 c:EquityFutureandForwardMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:DesignatedAsHedgingInstrumentMember 2019-03-31 0000831001 us-gaap:CreditRiskContractMember us-gaap:DesignatedAsHedgingInstrumentMember <