XML 88 R60.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans and Allowances for Credit Losses, Loans by Portfolio Segment (Details) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Loans receivables disclosure [Abstract]    
Loans receivables with fixed rate of interest $ 4,259,974,000us-gaap_LoansReceivableWithFixedRatesOfInterest1 $ 4,327,636,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
Loans receivables with variable rate of interest 9,867,292,000us-gaap_LoansReceivableWithVariableRatesOfInterest1 8,363,479,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
Loan receivable non-accrual 80,771,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest 101,149,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
Total 14,208,037,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount 12,792,264,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Accruing loans past due (90 days) 125,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing [1] 1,415,000us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing [1]
Loans Receivable, Impaired, Foregone Interest on Nonaccrual Loans 8,170,000us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans 9,815,000us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans
Credit Commitments [Abstract]    
Outstanding commitments to extend credit 8,300,000,000us-gaap_UnusedCommitmentsToExtendCredit  
Outstanding standby letters of credit 448,000,000bokf_OutstandingStandbyLettersOfCredit  
Outstanding commercial letters of credit 6,700,000us-gaap_LettersOfCreditOutstandingAmount  
Commercial [Member]    
Loans receivables disclosure [Abstract]    
Loans receivables with fixed rate of interest 1,736,976,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 1,637,620,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
Loans receivables with variable rate of interest 7,345,167,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 6,288,841,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
Loan receivable non-accrual 13,527,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 16,760,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
Total 9,095,670,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 7,943,221,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
Energy [Member]    
Loans receivables disclosure [Abstract]    
Total 2,860,428,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember		 2,351,760,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
Services [Member]    
Loans receivables disclosure [Abstract]    
Total 2,518,229,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember		 2,282,210,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
Commercial Real Estate [Member]    
Loans receivables disclosure [Abstract]    
Loans receivables with fixed rate of interest 721,513,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 770,908,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Loans receivables with variable rate of interest 1,988,080,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 1,603,595,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Loan receivable non-accrual 18,557,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 40,850,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Total 2,728,150,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 2,415,353,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Residential Mortgage [Member]    
Loans receivables disclosure [Abstract]    
Loans receivables with fixed rate of interest 1,698,620,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 1,783,614,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Loans receivables with variable rate of interest 202,771,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 226,092,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Loan receivable non-accrual 48,121,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 42,320,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Total 1,949,512,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 2,052,026,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Permanent mortgage [Member]    
Loans receivables disclosure [Abstract]    
Total 969,951,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember		 1,062,744,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember
Loans receivable, other information [Abstract]    
Minimum FICO required for jumbo loan approval 720bokf_MinimumFicoRequiredForLoanApproval
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember		  
Maximum debt-to-income ratio on jumbo loans (in hundredths) 38.00%bokf_MaximumDebtToIncomeRatioOnLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember		  
Minimum loan-to-value ratio on jumbo loans (in hundredths) 60.00%bokf_MinimumLoanToValueRatioOnLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember		  
Maximum loan-to-value ratio on jumbo loans (in hundredths) 100.00%bokf_MaximumLoanToValueRatioOnLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentResidentialMortgageMember		  
Minimum period for fixed rate on variable rate jumbo loans (in years) 3 years  
Maximum period for fixed rate on variable rate jumbo loans (in years) 10 years  
Permanent mortgages guaranteed by U.S. government agencies [Member]    
Loans receivables disclosure [Abstract]    
Total 205,950,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember		 181,598,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_PermanentMortgagesGuaranteedByUsGovernmentAgenciesMember
Home equity    
Loans receivables disclosure [Abstract]    
Total 773,611,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		 807,684,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Loans receivable, other information [Abstract]    
Percentage of home equity portfolio comprised of first lien loans 69.00%bokf_PercentageOfHomeEquityPortfolioComprisedOfFirstLienLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		 70.00%bokf_PercentageOfHomeEquityPortfolioComprisedOfFirstLienLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Percentage of home equity portfolio comprised of junior lien loans 31.00%bokf_PercentageOfHomeEquityPortfolioComprisedOfJuniorLienLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		 30.00%bokf_PercentageOfHomeEquityPortfolioComprisedOfJuniorLienLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Percentage of junior lien home equity loans that are amortizing term loans 71.00%bokf_PercentageOfJuniorLienHomeEquityLoansThatAreAmortizingTermLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		 74.00%bokf_PercentageOfJuniorLienHomeEquityLoansThatAreAmortizingTermLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Percentage of junior lien home equity loans that are revolving lines of credit 29.00%bokf_PercentageOfJuniorLienHomeEquityLoansThatAreRevolvingLinesOfCredit
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		 26.00%bokf_PercentageOfJuniorLienHomeEquityLoansThatAreRevolvingLinesOfCredit
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember
Home equity loans, description Home equity loans generally require a minimum FICO score of 700 and a maximum DTI of 40%.  
Home equity loans, maximum 400,000bokf_HomeEquityLoansMaximum
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_HomeEquityMember		  
Home equity loans, revolving period 5 years  
Home equity loans, amortization period following revolving period 15 years  
Home equity loans, discretionary additional revolving period 5 years  
Consumer [Member]    
Loans receivables disclosure [Abstract]    
Loans receivables with fixed rate of interest 102,865,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 135,494,000us-gaap_LoansReceivableWithFixedRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Loans receivables with variable rate of interest 331,274,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 244,951,000us-gaap_LoansReceivableWithVariableRatesOfInterest1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Loan receivable non-accrual 566,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 1,219,000us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Total 434,705,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 381,664,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Geographic Concentration Risk [Member] | Texas [Member]    
Loans receivables disclosure [Abstract]    
Total 4,900,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX		 4,300,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX
Loans receivable, other information [Abstract]    
Percentage of loan portfolio attributed to Texas 34.00%bokf_PercentageofLoanPortfolioAttributedtoTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX		 34.00%bokf_PercentageofLoanPortfolioAttributedtoTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX
Geographic Concentration Risk [Member] | Texas [Member] | Commercial [Member]    
Loans receivables disclosure [Abstract]    
Total 3,200,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX		 2,800,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX
Loans receivable, other information [Abstract]    
Percentage of loan portfolio attributed to Texas 36.00%bokf_PercentageofLoanPortfolioAttributedtoTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX		 36.00%bokf_PercentageofLoanPortfolioAttributedtoTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX
Geographic Concentration Risk [Member] | Texas [Member] | Commercial Real Estate [Member]    
Loans receivable, other information [Abstract]    
Percentage of loan portfolio secured by property in Texas (in hundredths) 34.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX		 32.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX
Geographic Concentration Risk [Member] | Texas [Member] | Residential Mortgage [Member]    
Loans receivable, other information [Abstract]    
Percentage of loan portfolio secured by property in Texas (in hundredths) 28.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX		 27.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInTexas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_TX
Geographic Concentration Risk [Member] | Oklahoma [Member]    
Loans receivables disclosure [Abstract]    
Total 3,400,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK		 3,300,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK
Loans receivable, other information [Abstract]    
Percentage of loan portfolio attributed to Oklahoma 24.00%bokf_PercentageofLoanPortfolioAttributedtoOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK		 26.00%bokf_PercentageofLoanPortfolioAttributedtoOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK
Geographic Concentration Risk [Member] | Oklahoma [Member] | Commercial [Member]    
Loans receivables disclosure [Abstract]    
Total 2,000,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK		 1,900,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK
Loans receivable, other information [Abstract]    
Percentage of loan portfolio attributed to Oklahoma 22.00%bokf_PercentageofLoanPortfolioAttributedtoOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK		 23.00%bokf_PercentageofLoanPortfolioAttributedtoOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK
Geographic Concentration Risk [Member] | Oklahoma [Member] | Commercial Real Estate [Member]    
Loans receivable, other information [Abstract]    
Percentage of loan portfolio secured by property in Oklahoma (in hundredths) 16.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK		 19.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK
Geographic Concentration Risk [Member] | Oklahoma [Member] | Residential Mortgage [Member]    
Loans receivable, other information [Abstract]    
Percentage of loan portfolio secured by property in Oklahoma (in hundredths) 38.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK		 38.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyInOklahoma
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_OK
Geographic Concentration Risk [Member] | New Mexico [Memnber] | Commercial Real Estate [Member]    
Loans receivable, other information [Abstract]    
Percentage of loan portfolio secured by property in New Mexico (in hundredths)   11.00%bokf_PercentageofLoanPortfolioSecuredByPropertyinNewMexico
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_NM
Geographic Concentration Risk [Member] | New Mexico [Memnber] | Residential Mortgage [Member]    
Loans receivable, other information [Abstract]    
Percentage of loan portfolio secured by property in New Mexico (in hundredths) 12.00%bokf_PercentageofLoanPortfolioSecuredByPropertyinNewMexico
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_NM		 10.00%bokf_PercentageofLoanPortfolioSecuredByPropertyinNewMexico
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_NM
Geographic Concentration Risk [Member] | Colorado [Member] | Residential Mortgage [Member]    
Loans receivable, other information [Abstract]    
Percentage of loan portfolio secured by property in Colorado (in hundredths) 10.00%bokf_PercentageOfLoanPortfolioSecuredByPropertyinColorado
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_GeographicConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_StatementGeographicalAxis
= stpr_CO		  
Credit Concentration Risk [Member] | Energy [Member]    
Loans receivables disclosure [Abstract]    
Total 2,900,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember		 2,400,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember
Loans receivable, other information [Abstract]    
Percentage of energy loans in loan portfolio 20.00%bokf_PercentageOfEnergyLoansInLoanPortfolio
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyMember		  
Credit Concentration Risk [Member] | Energy Producers [Member]    
Loans receivables disclosure [Abstract]    
Total 2,500,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyProducersMember		  
Loans receivable, other information [Abstract]    
Percentage of committed energy production loans secured by oil 59.00%bokf_PercentageOfCommittedEnergyProductionLoansSecuredByOil
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyProducersMember		  
Percentage of committed energy production loans secured by natural gas 41.00%bokf_PercentageOfCommittedEnergyProductionLoansSecuredByNaturalGas
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_EnergyProducersMember		  
Credit Concentration Risk [Member] | Services [Member]    
Loans receivables disclosure [Abstract]    
Total 2,500,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember		 2,300,000,000us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
Loans receivable, other information [Abstract]    
Amount of loans with individual balances less than $10 million 1,200,000,000bokf_MaximumAmountOfLoansWithBalancesBelowThreshold
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember		 1,100,000,000bokf_MaximumAmountOfLoansWithBalancesBelowThreshold
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
Maximum loan amount for certain individual loans in category $ 10,000,000bokf_MaximumLoanAmountForCertainIndividualLoansInCategory
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember		 $ 10,000,000bokf_MaximumLoanAmountForCertainIndividualLoansInCategory
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CreditConcentrationRiskMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= bokf_ServicesMember
[1] Excludes residential mortgage loans guaranteed by agencies of the U.S. government