Debt Disclosure [Abstract] Other Borrowed Funds [Text Block] Debt Disclosure [Text Block] Loans and Leases Receivable, Net Amount [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Commercial [Member] Commercial Portfolio Segment [Member] Commercial Real Estate [Member] Commercial Real Estate Portfolio Segment [Member] Residential Mortgage [Member] Residential Portfolio Segment [Member] Personal [Member] Consumer Portfolio Segment [Member] Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Class of Financing Receivables [Domain] Class of Financing Receivable [Domain] Services [Member] Services [Member] Class of financing receivables related to services industry Energy [Member] Energy [Member] Class of financing receivables related to energy industry Energy Producers [Member] Energy Producers [Member] Energy Producers [Member] Healthcare [Member] Health Care [Member] Permanent mortgage [Member] Permanent Residential Mortgage [Member] Class of financing receivables related to mortgages of permanent residences. Permanent mortgages guaranteed by U.S. government agencies [Member] Permanent Mortgages Guaranteed by US Government Agencies [Member] Class of financing receivables related to mortages for permanent residences guaranteed by U.S. government agencies. Home equity [Member] Home Equity Line of Credit [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Type [Domain] Geographic Concentration Risk [Member] Geographic Concentration Risk [Member] Credit Concentration Risk [Member] Credit Concentration Risk [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Texas [Member] TEXAS Oklahoma [Member] OKLAHOMA Colorado [Member] COLORADO Loans Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Loans receivables disclosure [Abstract] Loans and Leases Receivable Disclosure [Abstract] Loans receivables with fixed rate of interest Loans Receivable with Fixed Rates of Interest Loans receivables with variable rate of interest Loans Receivable with Variable Rates of Interest Loan receivable non-accrual Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest Total Loans and Leases Receivable, Gross Accruing loans past due (90 days) Financing Receivable, 90 Days or More Past Due, Still Accruing Foregone interest on nonaccrual loans Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans Loans receivable, other information [Abstract] Loans and Leases Receivable, Other Information [Abstract] Percentage of loan class to total loans Percentage of Loan Class to Total Loans Represents percentage of given loan class to total loans. Amount of loans with individual balances less than $10 million Maximum Amount Of Loans With Balances Below Threshold Maximum dollar amount of loans in this category with individual loan amount less than specified threshold. Maximum loan amount for certain individual loans in category Maximum Loan Amount For Certain Individual Loans In Category Maximum loan amount for specified individual loans in category. Percentage of committed energy production loans secured by oil Percentage of committed energy production loans secured by oil Percentage of committed energy production loans secured by properties primarily producing oil Percentage of committed energy production loans secured by natural gas Percentage of committed energy production loans secured by natural gas Percentage of committed energy production loans secured by properties producing natural gas Percentage of loan portfolio secured by property in Texas (in hundredths) Percentage of Loan Portfolio Secured By Property in Texas Reflects the percentage of the loan in portfolio secured by property in the state of Texas. Percentage of loan portfolio secured by property in Oklahoma (in hundredths) Percentage of Loan Portfolio Secured By Property in Oklahoma Reflects the percentage of the loan in portfolio secured by property in the state of Oklahoma. Percentage of loan portfolio secured by property in Colorado (in hundredths) Percentage Of Loan Portfolio Secured By Property in Colorado Percentage Of Loan Portfolio Secured By Property in Colorado Minimum FICO required for jumbo loan approval Minimum FICO Required For Loan Approval Represents the minimum FICO score required for loan approval. Maximum debt-to-income ratio on jumbo loans (in hundredths) Maximum Debt To Income Ratio On Loans Represents the maximum debt-to-income (DTI) ratio on loans approved. Minimum loan-to-value ratio on jumbo loans (in hundredths) Minimum Loan To Value Ratio On Loans Represents the minimum loan-to-value (LTV) ratio acceptable for loans to be approved. Maximum loan-to-value ratio on jumbo loans (in hundredths) Maximum Loan To Value Ratio On Loans Represents the maximum loan-to-value (LTV) ratio on loans approved. Minimum period for fixed rate on variable rate jumbo loans (in years) Minimum Period For Fixed Rate On Variable Rate Jumbo Residential Mortgage Loans The minimum number o years that a variable rate jumbo residential mortgage loan will have a fixed rate of interest. Maximum period for fixed rate on variable rate jumbo loans (in years) Maximum Period for Fixed Rate on Variable Rate Jumbo Residential Mortgage Loan Represent the maximum number of years that a variable rate jumbo residential mortgage loan will have a fixed rate of interest. Percentage of home equity portfolio comprised of first lien loans Percentage of home equity portfolio comprised of first lien loans Percentage of home equity portfolio comprised of first lien loans Percentage of home equity portfolio comprised of junior lien loans Percentage of home equity portfolio comprised of junior lien loans Percentage of home equity portfolio comprised of junior lien loans Percentage of junior lien home equity loans that are amortizing term loans Percentage of junior lien home equity loans that are amortizing term loans Percentage of junior lien home equity loans that are amortizing term loans Percentage of junior lien home equity loans that are revolving lines of credit Percentage of junior lien home equity loans that are revolving lines of credit Percentage of junior lien home equity loans that are revolving lines of credit Home equity loans, description Home equity loans, description Describes the general components and status of home equity loans serviced by the entity outstanding as of the Balance Sheet date. Home equity loans, revolving period Revolving Period for Home Equity Loans Represents the revolving period for home equity loans. Home equity loans, amortization period following revolving period Amortization Period Following Revolving Period for Home Equity Loans Represents the amortization period of repayment following the revolving period for home equity loans. Home equity loans, discretionary additional revolving period Home equity loans, discretionary additional revolving period Represent additional revolving period that may be extended at the discretion of management. Credit Commitments [Abstract] Credit Commitments [Abstract] -- None. No documentation exists for this element. -- Outstanding commitments to extend credit Unused Commitments to Extend Credit Outstanding standby letters of credit Outstanding Standby Letters of Credit An irrevocable guarantee to extend credit to a party based on current credit policies. Outstanding commercial letters of credit Letters of Credit Outstanding, Amount Share-based Payment Arrangement [Abstract] Share-Based Compensation Plans [Text Block] Share-based Payment Arrangement [Text Block] Condensed Financial Information Disclosure [Abstract] Condensed Financial Information of Parent Company Only Disclosure [Text Block] Condensed Financial Information of Parent Company Only Disclosure [Text Block] Income Statement [Abstract] Interest and dividend revenue [Abstract] Interest Income (Expense), Net [Abstract] Loans Interest and Fee Income, Loans and Leases Held-in-portfolio Residential mortgage loans held for sale Interest and Fee Income, Loans Held-for-sale, Mortgages Trading securities Interest and Dividend Income, Securities, Operating, Trading or Measured at Fair Value Investment securities Interest Income, Debt Securities, Held-to-maturity Available for sale securities Interest and Dividend Income, Securities, Operating, Available-for-sale Fair value option securities Interest revenue on fair value option securities Interest income from fair value option securities that the Company has elected to carry at fair value and separately identify in the Consolidated Balance Sheets with changes in the fair value recognized in earnings as they occur. Restricted equity securities Other Interest and Dividend Income Interest-bearing cash and cash equivalents Interest income, Interest-bearing cash and cash equivalents Interest earned from money market and other interest-bearing accounts held with domestic financial institutions, from excess federal funds sold to another commercial bank requiring such for its legal reserve requirements and from securities purchased under agreements to resell. Total interest revenue Interest and Dividend Income, Operating Interest Expense [Abstract] Interest Expense [Abstract] Deposits Interest Expense, Deposits Borrowed funds Interest Expense, Short-term Borrowings Subordinated debentures Interest Expense, Subordinated Notes and Debentures Total interest expense Interest Expense Net interest and dividend revenue Interest Income (Expense), Net Provision for credit losses Provision for Loan, Lease, and Other Losses Net interest and dividend revenue after provision for credit losses Interest Income (Expense), after Provision for Loan Loss Other operating revenue [Abstract] Noninterest Income [Abstract] Statement [Table] Statement [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Brokerage and trading revenue [Member] Brokerage and trading revenue [Member] Brokerage and trading revenue [Member] Transaction card revenue [Member] Transaction card revenue [Member] Transaction card revenue [Member] Fiduciary and asset management revenue [Member] Fiduciary and Trust [Member] Deposit service charges and fees [Member] Deposit Account [Member] Mortgage banking revenue [Member] Mortgage Banking [Member] Other revenue [Member] Financial Service, Other [Member] Statement [Line Items] Statement [Line Items] Total fees and commissions Total fees and commissions Total fees and commissions earned from providing services such as maintaining: depositor accounts; fiduciary and trust; brokerage and underwriting; mortgage; transaction cards; and other revenue such as bank owned life insurance. Other gains (losses), net Gain (Loss) on Disposition of Assets Gain (loss) on derivatives, net Gain (Loss) from Price Risk Management Activity Gain (loss) on fair value option securities, net Gain on fair value option securities, net Gain (loss) included in earning for the period related fair value option securities primarily held as an economic hedge of the changes in the fair value of mortgage servicing rights. Change in fair value of mortgage servicing rights Mortgage Servicing Rights (MSR) Impairment (Recovery) Gain (loss) on available for sale securities, net Debt Securities, Realized Gain (Loss) Total other operating revenue Noninterest Income Other operating expense [Abstract] Noninterest Expense [Abstract] Personnel Labor and Related Expense Business promotion Marketing and Advertising Expense Charitable contributions to BOKF Foundation Contributions To BOKF Foundation Expense related to charitable contributions to BOK Foundation Professional fees and services Professional Fees Net occupancy and equipment Occupancy, Net Insurance Federal Deposit Insurance Corporation Premium Expense Data processing and communications Communications and Information Technology Printing, postage and supplies Supplies and Postage Expense Net losses and operating expenses of repossessed assets Gains (Losses) on Sales of Other Real Estate Amortization of intangible assets Amortization of Intangible Assets Mortgage banking costs Mortgage banking costs Expense related to mortgage banking activities including amortization of capitalized mortgage servicing rights, provision for losses on mortgage loans sold with recourse and other mortgage banking expenses. Other expense Other Noninterest Expense Total other operating expense Noninterest Expense Net income before taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Federal and state income taxes Income Tax Expense (Benefit) Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income (loss) attributable to Non-controlling interests Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to BOK Financial Corporation shareholders Net Income (Loss) Attributable to Parent Earnings per share: [Abstract] Earnings Per Share [Abstract] Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Average shares used in computation: [Abstract] Weighted Average Number of Shares Outstanding, Basic [Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Dividends declared per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Schedule of Impaired Loans [Table] Schedule of Impaired Financing Receivable [Table] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Domain] Financial Instrument Performance Status [Domain] Performing Financial Instruments [Member] Performing Financial Instruments [Member] Nonaccrual [Member] Nonperforming Financial Instruments [Member] Wholesale/retail [Member] Wholesale and retail [Member] Class of financing receivables related to wholesale/retail industry. Manufacturing [Member] Manufacturing [Member] Class of financing receivables related to manufacturing industry. Public finance [Member] Public Finance [Member] Class of financing receivables related to public finance Other commercial and industrial [Member] Other Commercial and Industrial [Member] Class of financing receivables related to other commercial and industrial industry. Residential construction and land development [Member] Residential construction and land development [Member] Residential construction and land development [Member] Retail [Member] Retail [Member] Office [Member] Office [Member] Class of financing receivables related for which repayment will come from the sale or rental of office space. Multifamily [Member] Multifamily [Member] Industrial [Member] Industrial [Member] Class of financing receivables for which repayment will come from the sale or rental of industrial facilities. Other commercial real estate [Member] Other Commercial Real Estate [Member] Class of financing receivables for which repyament is expected from the sale or rental of other commercial real estate properties. Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Impaired loans [Abstract] Loan and Lease Receivables, Impaired [Abstract] Impaired loans, unpaid principal balance Impaired Financing Receivable, Unpaid Principal Balance Impaired loans, recorded investment, total Impaired Financing Receivable, Recorded Investment Impaired loans, recorded investment with no related allowance Impaired Financing Receivable, with No Related Allowance, Recorded Investment Impaired loans, recorded investment with related allowance Impaired Financing Receivable, with Related Allowance, Recorded Investment Impaired loans, related allowance Impaired Financing Receivable, Related Allowance Impaired loans, average recorded investment Impaired Financing Receivable, Average Recorded Investment Impaired loans, interest income recognized Impaired Financing Receivable, Interest Income, Accrual Method Deposits [Abstract] Interest Expense on Deposits Disclosure [Table Text Block] Interest Income and Interest Expense Disclosure [Table Text Block] Fair Value Disclosures [Abstract] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Nonrecurring [Member] Fair Value, Nonrecurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Asset Class [Axis] Asset Class [Axis] Fair Value by Asset Class [Domain] Asset Class [Domain] Impaired Loans [Member] Fair Value, Impaired Loans [Member] Fair Value, Impaired Loans [Member] Real estate and other repossessed assets [Member] Fair Value, Real estate and other repossessed assets [Member] Fair Value, Real estate and other repossessed assets [Member] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Plan [Member] Pension Plan [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Assets, Fair Value Disclosure Assets, Fair Value Disclosure Gross charge-offs against allowance for loan losses Allowance for Loan and Lease Losses, Write-offs Net losses and expenses of repossessed assets, net Repossessed Assets Expense And Net Losses Amount of expense and net losses recognized during the period for repossessed assets. Defined Benefit Plan, Plan Assets, Amount Defined Benefit Plan, Plan Assets, Amount Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Stock Options [Member] Share-based Payment Arrangement, Option [Member] Restricted Stock [Member] Restricted Stock [Member] Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] Share-based Compensation Arrangements by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Share-based Compensation Arrangements by Share-based Payment Award, Options, Outstanding, Number of Options [Abstract] Number of Options [Abstract] [Abstract] Number of Options [Abstract] [Abstract] Number of options outstanding, Ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Share-based Compensation Arrangements by Share-based Payment Award, Options, Weighted Average Exercise Price [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Options outstanding, weighted average exercise price, ending balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options vested, weighted average exercise price (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Share-based Compensation Arrangements by Share-based Payment Award, Options, Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Options outstanding, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Options vested, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Options exercised, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Weighted average remaining contractual life of options outstanding (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted average remaining contractual life of options vested (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Share-based Compensation Arrangements by Share-based Payment Award, Restricted Stock, Nonvested, Number of Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Non-vested shares awarded, beginning of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Non-vested shares that were granted during the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Non-vested shares that vested during period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Non-vested shares that forfeited during period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Non-vested shares awarded, end of period (in shares) Share-based Compensation Arrangements by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted Average Grant Date Fair Value, Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted average grant date fair value non-vested share awards forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Share-based Compensation Costs, Including Costs That May Be Recognized As Future Expense [Abstract] Share-based Compensation Costs, Inclduing Costs That May Be Recognized As Future Expense [Abstract] Compensation Expense share-based compensation, including costs that may be recognized as future expense Share-based Compensation Expense Recognized Share-based Payment Arrangement, Expense Unrecognized compensation cost of unvested awards, for future periods Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Unrecognized compensation cost of unvested awards, Amount to be expensed in 2020 Employee Service Share-based Compensation, Nonvested Awards, Compensation Costs Not Yet Recognized, Amount to be Expensed in Next Twelve Months Represents the unrecognized cost of unvested share-based compensation awards to be recognized in expense in the net twelve months following the balance sheet date. Unrecognized compensation cost of unvested awards, Amount to be expensed in 2021 Employee Service Share-based Compensation, Nonvested Awards, Compensation Costs Not Yet Recognized, Amount to be Expensed in Year Two Represents the unrecognized cost of unvested share-based compensation awards to be recognized in expense in the second year following the balance sheet date. Unrecognized compensation cost of unvested awards, Amount to be expensed in 2022 Employee Service Share-based Compensation, Nonvested Awards, Compensation Costs Not Yet Recognized, Amount to be Expensed in Year Three Represents the unrecognized cost of unvested share-based compensation awards to be recognized in expense in year three following the balance sheet date. Number of shares with required performance obligations Number of shares with required performance obligations Number of shares with required performance obligations Debt Securities, Held-to-maturity [Abstract] Debt Securities, Held-to-maturity [Table] Debt Securities, Held-to-maturity [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Fixed maturity securities [Member] Fixed Income Securities [Member] Municipal and other tax-exempt securities [Member] US States and Political Subdivisions Debt Securities [Member] Other debt securities [Member] Other Debt Obligations [Member] Residential agency mortgage-backed securities [Member] Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Schedule of Investment (Held-to-Maturity) Securities [Line Items] Schedule of Held-to-maturity Securities [Line Items] Investment Securities, Amortized Cost Debt Securities, Held-to-maturity Investment Securities, fair value Debt Securities, Held-to-maturity, Fair Value Investment Securities, Gross Unrealized Gain Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain Investment Securities, Gross Unrealized Loss Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss Investment Securities, Debt Maturities [Abstract] Debt Securities, Held-to-maturity, Maturity [Abstract] Investment Securities, Debt Maturities, Net, Amortized Cost [Abstract] Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract] Investment Securities, Debt Maturities, Less than One Year, Net Carrying Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Investment Securities, Debt Maturities, One to Five Years, Net Carrying Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost Investment Securities, Debt Maturities, Six to Ten Years, Net Carrying Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost Investment Securities, Debt Maturities, Over Ten Years, Net Carrying Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Investment Securities, Debt Maturities, Single Maturity Date, Carrying Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost Investment Securities, Debt Maturities, without Single Maturity Date, Net Carrying value Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Amortized Cost Investment Securities, Amortized Cost Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Debt Securities, Held-to-maturity, Maturity, Fair Value, Rolling Maturity [Abstract] Investment Securities, Debt Maturities, Less than One Year, Fair Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Investment Securities, Debt Maturities, One to Five Years, Fair Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Investment Securities, Debt Maturities, Six to Ten Years, Fair Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value Investment Securities, Debt Maturities, Over Ten Years, Fair Value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Investment Securities, Debt Maturities, Single Maturity Date, Fair value Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value Investment Securities, Debt Maturities, without Single Maturity Date, Fair value Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value Investment Securities, Debt Maturities, Weighted Average Maturity Held-to-maturity Securities, Debt Maturities, Weighted Average Maturity Represents the weighted average maturity (weighted by amount of the security) of all securities in this investment type. Investment Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities Held-to-maturity Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities The calculated weighted-average expected life of mortgage-backed securities held to maturity based on prepayment assumptions as of the balance sheet date. Investment Securities, Continuous Unrealized Loss Position [Abstract] Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position [Abstract] Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract] Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value Investment Securities, Continuous Unrealized Loss Position, Fair Value Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract] Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract] Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Losses Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Losses Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of Goodwill [Table Text Block] Schedule of Goodwill [Table Text Block] Debt Securities, Trading, and Equity Securities, FV-NI [Abstract] Schedule of Trading Securities [Table] Debt Securities, Trading, and Equity Securities, FV-NI [Table] U.S. government agency debentures [Member] US Treasury and Government [Member] Asset-backed securities [Member] Asset-backed Securities, Securitized Loans and Receivables [Member] Schedule of Trading Securities [Line Items] Debt and Equity Securities, FV-NI [Line Items] Trading securities Debt Securities, Trading Trading Securities, Net Unrealized Gain (Loss) Trading Securities, Net Unrealized Gains (Losses) Represents the unrealized holding gain or loss included in the fair value of trading securities as of the balance sheet date. Numerator: [Abstract]: Numerator: [Abstract] -- None. No documentation exists for this element. -- Net income attributable to BOK Financial Corp. shareholders Less: Earnings allocated to participating securities Undistributed Earnings (Loss) Allocated to Participating Securities, Basic Numerator for basic earnings per share - income available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Effect of reallocating undistributed earnings of participating securities Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted Numerator for diluted earnings per share - income available to common shareholders Net Income (Loss) Available to Common Stockholders, Diluted Denominator: [Abstract] Denominator: [Abstract] -- None. No documentation exists for this element. -- Weighted average shares outstanding Weighted Average Number of Shares Outstanding, Basic and Diluted Less: Participating securities included in weighted average shares outstanding (in shares) Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights Denominator for basic earnings per common share (in shares) Dilutive effect of employee stock compensation plans (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Denominator for diluted earnings per common share (in shares) Diluted earnings per share (per share) Retirement Benefits [Abstract] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Retirement Plan Name [Axis] Retirement Plan Name [Axis] Retirement Plan Name [Domain] Retirement Plan Name [Domain] BOK Financial Pension Plan [Member] BOK Financial Pension Plan [Member] BOK Financial Pension Plan [Member] BOK Financial 401(k) Plan [Member] BOK Financial 401(k) Plan [Member] BOK Financial 401(k) Plan [Member] BOK Financial Pension Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] BOK Financial Pension Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Equity Securities [Member] Equity Securities [Member] Bonds [Member] Bonds [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Defined Benefit Plans and Other Postretirement Benefit Plans[Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] BOK Financial Pension Plan [Abstract] Defined Benefit Plan, Information about Plan Assets [Abstract] Interest percentage added to the five-year trailing average of five-year Treasury Securities Defined Benefit Plan, Interest Percentage Accrued On Employee Account Balances (Rate to Add to Treasury Securities Rate) Represents percentage added to five-year trailing average of five-year Treasury securities used in determining the interest accrued on employees' account balances. Interest percentage accrued on employee account balances, Minimum Defined Benefit Plan Interest Percentage Accrued On Employee Account Balances (Minimum) Represents the minimum interest rate used to accrued to employee account balances. Interest percentage accrued on employee account balances, Maximum Defined Benefit Plan Interest Percentage Accrued on Employee Account Balances (Maximum) Defined Benefit Plan Interest Percentage Accrued on Employee Account Balances (Maximum) Quarterly variable interest percentage accrued on employee account balances, minimum Defined Benefit Plan, Quarterly Variable Interest Rate Accrued On Employee Account Balances, Minimum Represents the lower end of the range of variable interest rates used to accrued on employee account balances during the current year. Quarterly variable interest percentage accrued on employee account balances, maximum Defined Benefit Plan, Quarterly Variable Interest Rate Accrued on Employee Account Balances, Maximum Defined Benefit Plan, Quarterly Variable Interest Rate Accrued on Employee Account Balances, Maximum Defined Benefit Plan, Benefit Obligation Defined Benefit Plan, Benefit Obligation Net periodic benefit cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Total estimated future benefit payments Defined Benefit Plan Expected Future Benefit Payments Total The total amount of expected future benefit payments under a defined benefit plan. Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Defined Benefit Plan, Plan Assets, Target Allocation, Percentage BOK Financial Pension Plan Weighted-average Assumptions [Abstract] Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate (in hundredths) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected return on plan assets (in hundredths) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets BOK Financial 401(k) Plan [Abstract] Defined Contribution Plan [Abstract] Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Defined Contribution Plan, Employer Matching Contribution, Percent of Match Defined Contribution Plan, Employer Matching Contribution, Percent of Match Defined Contribution Plan, Minimum Years of Service for Employees to Obtain Maximum Employer Matching Defined Contribution Plan, Minimum Years of Service for Employees to Obtain Maximum Employer Matching The minimum years of service for employees to obtain maximum employer matching under a defined contribution plan. Defined Contribution Plan, Maximum Years of Service for Employees to Obtain Minimum Employer Matching Defined Contribution Plan, Maximum Years of Service for Employees to Obtain Minimum Employer Matching The maximum years of service for employees to obtain minimum employer matching under a defined contribution plan. Contributions Non-Elective Annual Contributions For Qualified Employees Contributions Non-Elective Annual Contributions For Qualified Employees Non-elective annual contributions to a defined pension plan for qualified employees. Defined Contribution Plan, Annual Base Employee Compensation to Qualify for Non-Elective Employer Contributions, Maximum Defined Contribution Plan, Annual Base Employee Compensation to Qualify for Non-Elective Employer Contributions, Maximum The maximum annual base employee compensation to qualify for non-elective employer contributions under the deferred compensation plan. Defined Contribution Plan, Vesting Period for Employer Contributions Defined Contribution Plan, Vesting Period for Employer Contributions The vesting period for employer contributions to defined contribution plan. Defined Contribution Plan, Cost Defined Contribution Plan, Cost Property, Plant and Equipment [Abstract] Premises and Equipment [Table Text Block] Property, Plant and Equipment [Table Text Block] Fair Value, Recurring [Member] Fair Value, Recurring [Member] U.S. Treasury [Member] US Treasury Securities [Member] Residential non-agency mortgage-backed securities [Member] Mortgage-backed Securities, Issued by Private Enterprises [Member] Commercial agency mortgage-backed securities [Member] Commercial Mortgage Backed Securities [Member] Assets [Abstract] Assets [Abstract] Available for sale securities Debt Securities, Available-for-sale Fair value option securities Fair value option securities Fair value option securities represent securities the Company has elected to carry at fair value and separately identified on the balance sheet with changes in fair value recognized in earnings as they occur. Certain residential mortgage-backed securities issued by US government agencies are held as an economic hedge of changes in the fair value of mortgage servicing rights and related derivative contracts. In addition, other securities may be held to manage interest rate risk or for deferred compensation purposes. Securities held for interest rate risk management may be economically hedged by derivative contracts not designated as hedging instruments effectively modify these fixed rate securities into variable rate securities. Residential mortgage loans held for sale Mortgages Held-for-sale, Fair Value Disclosure Mortgage servicing rights Servicing Asset at Fair Value, Amount Derivative contracts, net of cash margin, Assets, Fair Value Derivative Asset Liabilities [Abstract] Liabilities [Abstract] Derivative contracts, net of cash margin, Liabilities, Fair Value Derivative Liability Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Acquired Finite-Lived Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Asset, Useful Life Finite-Lived Intangible Asset, Useful Life Stockholders' Equity Note [Abstract] Shareholders' Equity [Text Block] Stockholders' Equity Note Disclosure [Text Block] Income Tax Disclosure [Abstract] Federal and State Income Taxes [Text Block] Income Tax Disclosure [Text Block] Fair Value Measurements, Measured On Recurring Basis, Significant Unobservable Inputs, Quantitative Information [Abstract] Fair Value Measurements, Measured On Recurring Basis, Significant Unobservable Inputs, Quantitative Information [Abstract] Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Weighted Average [Member] Weighted Average [Member] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Discounted Cash Flow [Member] Valuation Technique, Discounted Cash Flow [Member] Quoted prices of loans sold in securitization transactions, with a liquidity discount applied [Member] Quoted prices of loans sold in securitization transactions, with a liquidity discount applied [Member] Quoted prices of loans sold in securitization transactions, with a liquidity discount applied [Member] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Interest Rate Spread [Member] Interest Rate Spread [Member] Interest Rate Spread [Member] Liquidity discount [Member] Measurement Input, Discount for Lack of Marketability [Member] Available-for-sale securities [Member] Available-for-sale Securities [Member] Residential mortgage loans held for sale [Member] Residential Mortgage Loans Held for Sale [Member] Represents financial statement line item Residential Mortgage Loans Held for Sale Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Range of Interest Rates used to Value Securities Range of Interest Rates used to Value Securities Range of Interest Rates used to Value Securities Range of fair value as a percentage of par value Range of fair value as a percentage of part value Range of fair value as a percentage of part value Liquidity Discount on Mortgage Loans Qualifying for Sale to US Govt Agencies Liquidity Discount on Mortgage Loans Qualifying for Sale to US Govt Agencies Represents a liquidity discount applied to the market value of mortgage loans qualifying for sale to U.S. government agencies when a mortgage loan is ineligible for sale to U.S. government agencies. Average Yields On Comparable Short-term Taxable Securities Average Yields On Comparable Short-term Taxable Securities Maximum The average rate of yield for comparable short-term investment grade taxable security. Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Business Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Residential Mortgage [Member] Residential Mortgage [Member] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Pass [Member] Pass [Member] Other Loans Especially Mentioned [Member] Special Mention [Member] Substandard [Member] Substandard [Member] Specific Allowance [Member] Specific Allowance [Member] Financing receivables and related allowance that have been spefically allocated to a portfolio segment. Nonspecific Allowance [Member] Unallocated Financing Receivables [Member] Financing Receivable, Credit Quality Indicator [Line Items] Financing Receivable, Credit Quality Indicator [Line Items] Recorded Investment [Abstract] Recorded Investment [Abstract] -- None. No documentation exists for this element. -- Internally Risk Graded, Recorded Investment Internally Risk Graded, Recorded Investment The amount of the recorded investment, that is internally risk graded on credit quality, in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Non-Graded, Recorded Investment Non-Graded, Recorded Investment The amount of the recorded investment, for which risk grading is not used to monitor credit quality, in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. These represent small homogeneous pools primarily composed of residential and consumers as well as certain commercial loans. Related Allowance [Abstract] Related Allowance [Abstract] -- None. No documentation exists for this element. -- Internally Risk Graded, Related Allowance Internally Risk Graded, Allowance The amount of the allowance for credit losses on recorded investment, that is internally risk graded, in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Non-Graded, Related Allowance Non-Graded, Allowance The amount of the allowance for credit losses on recorded investment that is not internally risk graded, in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Total, Related Allowance Loans and Leases Receivable, Allowance Condensed Cash Flow Statement [Table] Condensed Cash Flow Statement [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Parent Company [Member] Parent Company [Member] Condensed Cash Flow Statements, Captions [Line Items] Condensed Cash Flow Statements, Captions [Line Items] Cash Flows From Operating Activities: [Abstract] Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Adjustments to reconcile net income to net cash provided by operating activities: [Abstract] Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Equity in undistributed income of bank subsidiaries Equity in undistributed income of bank subsidiaries Represents the equity in undistributed income of consolidated bank subsidiaries by the parent for parent-only financial statement purposes. Equity in undistributed income of non-bank subsidiaries Equity in undistributed income of non-bank subsidiaries Represents equity in undistributed income of consolidated non-bank subsidiaries by parent for parent-only financial statement purposes. Change in other assets Increase (Decrease) in Other Operating Assets Change in other liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash Flows From Investing Activities: [Abstract] Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from sales of available for sale securities Proceeds from Sale of Debt Securities, Available-for-sale Investment in subsidiaries Investment in subsidiaries Investment in subsidiaries Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash Flows From Financing Activities: [Abstract] Net Cash Provided by (Used in) Financing Activities [Abstract] Net change in other borrowed funds Proceeds from (Repayments of) Debt Issuance of common and treasury stock, net Proceeds from Issuance of Common Stock Dividends paid Payments of Ordinary Dividends, Common Stock Repurchase of common stock Payments for Repurchase of Common Stock Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Marketable Securities [Abstract] Securities [Text Block] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Statement of Financial Position [Abstract] Cash and due from banks Cash and Due from Banks Interest-bearing cash and cash equivalents Interest-bearing Deposits in Banks and Other Financial Institutions Trading securities Debt Securities, Trading, and Equity Securities, FV-NI Investment securities Restricted equity securities Federal Home Loan Bank Stock and Federal Reserve Bank Stock Residential mortgage loans held for sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group Loans Allowance for loan losses Loans, net of allowance Loans and Leases Receivable, Net Amount Premises and equipment, net Property, Plant and Equipment, Net Receivables Accrued Investment Income Receivable Goodwill Goodwill Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Real estate and other repossessed assets, net of allowance Other Real Estate, Foreclosed Assets, and Repossessed Assets Derivative contracts Cash surrender value of bank-owned life insurance Bank Owned Life Insurance Receivable on unsettled securities sales Receivables from Brokers-Dealers and Clearing Organizations Other assets Other Assets Total assets Assets Liabilities and Equity [Abstract] Liabilities and Equity [Abstract] Deposits [Abstract] Noninterest-bearing demand deposits Noninterest-bearing Deposit Liabilities, Domestic Interest-bearing Deposit Liabilities [Abstract] Interest-bearing Deposit Liabilities [Abstract] Transaction Demand Deposit Accounts Savings Deposits, Savings Deposits Time Time Deposits Total deposits Deposits Funds purchased and repurchase agreements Federal Funds Purchased and Securities Sold under Agreements to Repurchase Other borrowings Other Borrowings Subordinated debentures Subordinated Debt Accrued interest, taxes and expense Accounts Payable and Accrued Liabilities Derivative contracts Due on unsettled securities purchases Broker-Dealer, Payable to Other Broker-Dealer and Clearing Organization Other liabilities Other Liabilities Total liabilities Liabilities Shareholders' equity: [Abstract] Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Capital surplus Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Treasury stock Treasury Stock, Value Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total shareholders’ equity Stockholders' Equity Attributable to Parent Non-controlling interests Stockholders' Equity Attributable to Noncontrolling Interest Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and equity Liabilities and Equity Accounting Policies [Abstract] Significant Accounting Policies [Text Block] Significant Accounting Policies [Text Block] Derivative Instrument Detail [Abstract] Trading Activities, Gain and Losses, by Type, by Income Statement Location [Table] Trading Activities, Gain and Losses, by Type, by Income Statement Location [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] To-be-announced residential mortgage-backed securities [Member] TBA Residential Mortgage-Backed Securities [Member] To-be-announed residential mortgage-backed securities [Member] Interest rate swaps [Member] Interest Rate Swap [Member] Energy contracts [Member] Energy Related Derivative [Member] Agricultural contracts [Member] Agricultural Contracts [Member] Trading in a derivative instrument whose primary underlying risk is tied to agricultural commodity prices. Foreign exchange contracts [Member] Foreign Exchange Contract [Member] Equity option contracts [Member] Equity Swap [Member] Total customer risk management programs [Member] Customer Risk Management Programs [Member] Represents total derivative contracts in customer risk management programs. Trading [Member] Trading [Member] Trading [Member] Internal risk management programs [Member] Internal Risk Management Programs [Member] Represents program to manage interest rate sensitivity, as part of its economic hedge of the changes in the fair value of mortgage servicing rights and as an economic hedge of trading securities. Trading Activity, Gains and Losses, Net [Line Items] Trading Activity, Gains and Losses, Net [Line Items] Brokerage and Trading Revenue Trading Gain (Loss) Gain (Loss) on Derivatives, Net Derivative, Gain (Loss) on Derivative, Net Securities, Fair Value Option Securities [Abstract] Securities, Fair Value Option Securities [Abstract] Fair Value Option Securities [Table] Fair Value Option Securities [Table] Fair Value Option Securities [Table] Fair Value Option Securities [Line Items] Fair Value Option Securities [Line Items] [Line Items] for Fair Value Option Securities [Table] Fair Value Option Securities Unrealized Gain or Loss Fair Value Option Securities Unrealized Gain or Loss Fair Value Option Securities Unrealized Gain or Loss Revenue from Contract with Customer [Abstract] Fees and Commissions Revenue [Text Block] Revenue from Contract with Customer [Text Block] Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Subsidiaries [Member] Subsidiaries [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] BOKF, NA [Member] BOKF, NA [Member] BOKF, NA [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Directors and Senior Management [Member] Management [Member] Director [Member] Director [Member] Executive Officer [Member] Executive Officer [Member] Affiliated Entity [Member] Affiliated Entity [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Loans and Leases Receivable, Related Parties [Roll Forward] Loans and Leases Receivable, Related Parties [Roll Forward] Beginning balance Loans and Leases Receivable, Related Parties Advances Loans and Leases Receivable, Related Parties, Additions Payments Loans and Leases Receivable, Related Parties, Proceeds Adjustments Loans and Leases Receivable Related Parties Adjustments Reflects the amount of adjustments made with related parties in the form of loans and lease receivables. Ending balance Loan Commitments and Equity Investments [Abstract] Loan Commitments and Equity Investments [Abstract] Loan Commitments and Equity Investments [Abstract] Maximum percentage of unimpaired capital on loan commitments and equity investments to a single affiliate (in hundredths) Maximum percentage of unimpaired capital on loan commitments and equity investments to a single affiliate The maximum percentage of unimpaired capital on loan commitments and equity investments to a single affiliate. Maximum percentage of unimpaired capital on loan commitments and equity investments to all affiliates (in hundredths) Maximum percentage of unimpaired capital on loan commitments and equity investments to all affiliates The maximum percentage of unimpaired capital on loan commitments and equity investments to all affiliates. Maximum loan commitments and equity investments to a single affiliate Maximum loan commitments and equity investments to a single affiliate The amount of maximum loan commitments and equity investments to a single affiliate. Maximum loan commitments and equity investments to all affiliates Maximum loan commitments and equity investments to all affiliates The amount of maximum loan commitments and equity investments to all affiliates. Largest loan commitment and equity investment to a single affiliate Largest loan commitment and equity investment to a single affiliate The amount of largest loan commitment and equity investment to a single affiliate. Aggregate loan commitment and equity investment to all affiliates Aggregate loan commitment and equity investment to all affiliates The aggregate amount of largest loan commitment and equity investment to all affiliates. Outstanding amounts to all affiliates Related Party Transaction, Due from (to) Related Party Largest amount outstanding to a single affiliate Largest amount outstanding to a single affiliate Largest amount outstanding to a single affiliate at balance sheet date Related Party Transaction, Expenses from Transactions with Related Party Related Party Transaction, Expenses from Transactions with Related Party Percentage of investment funds' assets held by clients Percentage of Investment Funds' Assets Held for Clients The percentage of an investment fund's assets help by a company's clients. Assets Held in Cavanal Hill Funds Assets Held in Investment Funds The amount of assets held in investment funds. Debt Securities, Available-for-sale [Abstract] Schedule of Available for Sale Securities [Table] Schedule of Available-for-sale Securities [Table] Residential Mortgage Backed Securities [Member] Residential Mortgage Backed Securities [Member] Available for Sale Securities [Line Items] Debt Securities, Available-for-sale [Line Items] Available for sale securities, Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Available for sale securities Available for sale securities, Gross Unrealized Gain Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Available for sale securities, Gross Unrealized Loss Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Available for Sale Securities, Debt Maturities [Abstract] Available-for-sale Securities, Debt Maturities [Abstract] Available for Sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract] Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] Available for sale securities, Debt Maturities, Less than One Year, Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Available for sale securities, Debt Maturities, One to Five Years, Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost Available for sale securities, Debt Maturities, Six to Ten Years, Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost Available for sale securities, Debt Maturities, Over Ten Years, Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Available for sale securities, Maturity, Allocated and Single Maturity Date, Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Available for sale securities, Maturity, without Single Maturity Date, Amortized Cost Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost Available for Sale Securities, Maturity, Fair Value, Rolling Maturity [Abstract] Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] Available for sale securities, Debt Maturities, Less Than One Year, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Available for sale securities, Debt Maturities, One to Five Years, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Available for sale securities, Debt Maturities, Six to Ten Years, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value Available for sale securities, Debt Maturities, Over Ten Years, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Available for sale securities, Debt Maturities, Single Maturity Date, Fair value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Available for sale securities, Debt Maturities, without Single Maturity Date, Fair value Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value Available for sale securities, Debt Maturities, Weighted Average Maturity Debt Securities, Available-for-sale Securities, Debt Maturities, Weighted Average Maturity Represents the the contractual weighted average maturity (weighted by amount of the security) for this portion of the available-for-sale securities portfolio. Available for sale securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities Debt Securities, Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities The calculated weighted-average expected life of mortgage-backed securities based on prepayment assumptions as of the balance sheet date. Available for Sale Securities, Realized Gain (Loss) [Abstract] Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract] Proceeds from sales of available for sale securities Available for sale securities, Gross realized gains Debt Securities, Available-for-sale, Realized Gain Available for sale securities, Gross realized losses Debt Securities, Available-for-sale, Realized Loss, Excluding Other-than-temporary Impairment Available for sale securities, Related federal and state income tax expense Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Available for sale securities, Pledged as Collateral, Fair Value Pledged Assets Separately Reported, Securities Pledged as Collateral, at Fair Value Condensed Income Statement [Table] Condensed Income Statement [Table] Dividends, interest and fees received from bank susidiaries [Member] Dividends, interest and fees received from bank susidiaries [Member] Dividends, interest and fees received from bank susidiaries [Member] Diviidends, interest and fees received from non-bank subsidiaries [Member] Diviidends, interest and fees received from non-bank subsidiaries [Member] Dividends, interest and fees received from non-bank subsidiaries [Member] Condensed Income Statements, Captions [Line Items] Condensed Income Statements, Captions [Line Items] Total revenue Revenues Interest expense Other operating expense Total expense Operating Expenses Net income before taxes, other losses, net, and equity in undistributed income of subsidiaries Net income before taxes and loss on equity securities not held for trading, net Net income before taxes and loss on equity securities not held for trading, net Other gains (losses), net Net income before taxes, other losses, net, and equity in undistributed income of subsidiaries Income before taxes and equity in undistributed income of subsidiaries Income before taxes and equity in undistributed income of subsidiaries Net income before equity in undistributed income of subsidiaries Income before equity in undistributed earnings of subsidiaries Income before equity in undistributed earnings of subsidiaries Equity in undistributed income of bank subsidiaries Schedule of the Loans by Portfolio Segment [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Rollforward of Allowance For Loan Losses And Accrual for Off-Balnace Sheet Credit Losses [Table Text Block] Financing Receivable, Allowance for Credit Loss [Table Text Block] Schedule of Credit Quality Indicators [Table Text Block] Financing Receivable Credit Quality Indicators [Table Text Block] Summary of Impaired Loans [Table Text Block] Impaired Financing Receivables [Table Text Block] Summary of Loans by Aging Status [Table Text Block] Financing Receivable, Past Due [Table Text Block] Statement of Stockholders' Equity [Abstract] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Capital Surplus [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Treasury Stock [Member] Treasury Stock [Member] Accumulated Other Comprehensive Income (Loss) [Member] AOCI Attributable to Parent [Member] Total Shareholders' Equity [Member] Parent [Member] Non-Controlling Interests [Member] Noncontrolling Interest [Member] Balance, beginning of period (in shares) Shares, Issued Balance, beginning of period Transition adjustment of new accounting principle Cumulative Effect of New Accounting Principle in Period of Adoption Balance, beginning of period, Adjusted Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance Other comprehensive income (loss), net Other Comprehensive Income (Loss), Net of Tax Repurchase of common stock (in shares) Stock Repurchased During Period, Shares Repurchase of common stock Treasury Stock, Value, Acquired, Par Value Method Stock options exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Stock options exercised Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense) Non-vested shares awarded, net (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Vesting of non-vested shares (in shares) Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Vesting of non-vested shares Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Share-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Cash dividends on common stock Dividends, Common Stock, Cash Capital calls and distributions, net Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Issuance of shares for CoBiz acquisition (in shares) Stock Issued During Period, Shares, Acquisitions Issuance of shares fro CoBiz acquisition Stock Issued During Period, Value, Acquisitions Reclassification of stranded accumulated other comprehensive loss to retained earnings related to tax reform Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act. Balance, end of period (in shares) Balance, end of period Employee Benefits [Text Block] Pension and Other Postretirement Benefits Disclosure [Text Block] Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] CoBiz Financial Inc. [Member] Cobiz Financial Inc. [Member] Cobiz Financial Inc. [Member] Switchgrass Holdings LLC [Member] Switchgrass Holdings LLC [Member] Switchgrass Holdings LLC [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Effective Date of Acquisition Business Acquisition, Effective Date of Acquisition Name of Acquired Entity Business Acquisition, Name of Acquired Entity Consideration Transferred Business Combination, Consideration Transferred Cash payments to acquire businesses Payments to Acquire Businesses, Gross Stock Issued During Period, Shares, Acquisitions Equity interests issued Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Goodwill Recognized, Description Business Combination, Goodwill Recognized, Description Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract] Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract] Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Premises and Equipment Disclosure [Text Block] Property, Plant and Equipment Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Assets [Member] Other Assets [Member] Other Liabilities [Member] Other Liabilities [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Segment Reporting [Abstract] Reportable Segments [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Subsequent Events [Abstract] Subsequent Events [Text Block] Subsequent Events [Text Block] Loss Contingency [Abstract] Loss Contingency [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Visa Membership [Member] Visa Membership [Member] Banks membership in the Visa network and it proportionate share of covered liabilities and benefits. Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Misuse of Revenues Pledged to Municipal Bonds [Member] Misuse of Revenues Pledged to Municipal Bonds [Member] Misuse of Revenues Pledged to Municipal Bonds [Member] Bank Participation in Fraudulent Sale of Securities by Principals [Member] Bank Participation in Fraudulent Sale of Securities by Principals [Member] Bank Participation in Fraudulent Sale of Securities by Principals [Member] Purchase of facilities from principals subject to SEC New Jersey proceedings [Member] Purchase of facilities from principals subject to SEC New Jersey proceedings [Member] Purchase of facilities from principals subject to SEC New Jersey proceedings [Member] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Judicial Ruling [Member] Judicial Ruling [Member] Pending Litigation [Member] Pending Litigation [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of Visa Class B Shares Owned by Entity (in shares) Common Stock Class B Shares Owned Number of common stock class B owned by the entity Number of Visa Class A Shares Visa Class B Shares Are Convertible To (in shares) Number of Visa Class A Shares Visa Class B Shares Are Convertible To Represents the number of Visa Class A shares that Visa Class B shares held by the Company are convertible to. Litigation Settlement [Abstract] Litigation Settlement [Abstract] Disgorged fees Disgorged fees Represents fees disgorged as a result of a settlement with a regulatory agency. Litigation Settlement, Expense Litigation Settlement, Amount Awarded to Other Party Loss Contingency, Number of Plaintiffs Loss Contingency, Number of Plaintiffs Principal amount of entered judgment against the principal individual and his wife Principal amount of entered judgment against the principal individual and his wife Principal amount of entered judgment against the principal individual and his wife Pre-judgment interest amount of entered judgment against the principal individual and his wife Pre-judgment interest amount of entered judgment against the principal individual and his wife Pre-judgment interest amount of entered judgment against the principal individual and his wife Outstanding principal accrued interest and other amounts upon sale of facilities securing payment of the bonds Outstanding principal accrued interest and other amounts upon sale of facilities securing payment of the bonds Outstanding principal accrued interest and other amounts upon sale of facilities securing payment of the bonds Alleged total of judgment against nursing home operator Alleged total of judgment against nursing home operator Alleged total of judgment against nursing home operator Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings Outstanding principal, accrued interest and other amounts required by bond documents Outstanding principal, accrued interest and other amounts required by bond documents Outstanding principal, accrued interest and other amounts required by bond documents Number of principals in SEC New Jersey proceedings Number of principals in SEC New Jersey proceedings Number of principals in SEC New Jersey proceedings Other Commitments [Abstract] Other Commitments [Abstract] The Net Asset Value of Units in Mutual Funds (per unit) Mutual Funds Managed Net Asset Value of Units in Mutual Funds Represents the net asset value of units in Cavanal Hill Funds that BOK Financial may, but is not obligated to purchase assets to maintain the net asset value. Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank Minimum Average Cash Balance Required to be Maintained at Federal Reserve by Subsidiary Bank Share-based Payment Arrangement, Option, Activity [Table Text Block] Share-based Payment Arrangement, Option, Activity [Table Text Block] Schedule of Nonvested Share Activity [Table Text Block] Schedule of Nonvested Share Activity [Table Text Block] Valuation assumptions used [Table Text Block] Defined Benefit Plan, Assumptions [Table Text Block] Share-based Payment Arrangement, Noncash Expense [Abstract] Vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Award Required Holding Period Share-based Compensation Arrangement by Share-based Payment Award, Award Required Holding Period Share-based Compensation Arrangement by Share-based Payment Award, Award Required Holding Period Following Vesting Period. Earnings Per Share [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Loans [Abstract] Loans [Abstract] Loans, Number of Days Past Due for a Non-Risk Graded Loan to be Placed on Nonaccruing Status Loans, Number of Days Past Due for a Non-Risk Graded Loan to be Placed on Nonaccruing Status Represents the number of days past due a non-risk graded loan has to be in order to be placed on nonaccruing status. Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Placed on Nonaccruing Status Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Placed on Nonaccruing Status The number of days following notification of a borrowers Chapter 7 bankruptcy that a non-risk graded loan is placed on nonaccruing status. Loans, Minimum Number of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Minimum No of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Minimum number of days after which past due non-risk graded loans are charged off Loans, Maximum Number of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Max No of Days After Which Past Due Non-Risk Graded Loans Are Charged Off Maximum number of days after which past due non-risk graded loans are charged off Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Charged Off Loans, Number of Days After Notification of Chapter 7 Bankruptcy Non-Risk Graded Loan is Charged Off Represents the number of days after notification of Chapter 7 bankruptcy for a non-risk graded loan to be charged off Statement of Comprehensive Income [Abstract] Other comprehensive income (loss), before income taxes: [Abstract] Other Comprehensive Income (Loss), before Tax [Abstract] Net change in unrealized gain (loss) Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax Reclassification adjustments included in earnings: [Abstract] Reclassification Adjustments Included in Earnings [Abstract] Reclassification Adjustments Included in Earnings [Abstract] Loss (gain) on available for sale securities, net Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Other comprehensive gain (loss), before income taxes Other Comprehensive Income (Loss), before Tax Federal and state income taxes Other Comprehensive Income (Loss), Tax Other comprehensive gain (loss), net of income taxes Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income (loss) attributable to non-controlling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive income attributable to BOK Financial Corp. shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Summary of Regulatory Capital Levels [Table Text Block] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Regulatory Capital [Abstract] Regulatory Capital [Abstract] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] CoBiz Bank [Member] CoBiz [Member] CoBiz [Member] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Common Equity Tier 1 Capital [Abstract] Common Equity Tier One Capital [Abstract] Common Equity Tier 1 Capital Ratio Required to be Well Capitalized Common Equity Tier 1 Capital Ratio Required to be Well Capitalized The common equity Tier 1 capital ratio (common equity Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. Minimum Capital Requirements, Common Equity Tier 1 to Risk Weighted Assets Common Equity Tier One Capital to Risk Weighted Assets Minimum Requirement The minimum common equity Tier 1 risk based capital ratio (common equity Tier 1 capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. Capital Conservation Buffer, Common Equity Tier 1 to Risk Weighted Assets Capital Conservation Buffer, Common Equity Tier One to Risk Weighted Assets Capital conservation buffer in excess of minimum common equity Tier 1 risk based capital ratio (common equity Tier 1 capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. Minimum Capital Requirement Including Capital Conservation Buffer, Common Equity Tier 1 to Risk Weighted Assets Minimum Capital Requirement Including Capital Conservation Buffer, Common equity Tier One to Risk Weighted Assets The minimum common equity Tier 1 risk based capital ratio (common equity Tier 1 capital divided by risk weighted assets), including capital conservation buffer, required for capital adequacy purposes under the regulatory framework for prompt corrective action. Common Equity Tier 1 Capital Common Equity Tier One Capital Common Equity Tier 1 Capital to Risk Weighted Assets Common Equity Tier One Capital Ratio Tier I Capital (to Risk Weighted Assets) [Abstract] Tier One Risk Based Capital [Abstract] Tier I Capital Ratio Required to be Well Capitalized Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Minimum Capital Requirement, Tier 1 Capital to Risk Weighted Assets Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Capital Conservation Buffer, Tier 1 Capital to Risk Weighted Assets Capital Conservation Buffer, Tier 1 Capital to Risk Weighted Assets The capital conservation buffer in excess of the minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. Minimum Capital Requirement Including Capital Conservation Buffer, Tier One to Risk Weighted Assets Minimum Capital Requirement Including Capital Conservation Buffer, Tier One to Risk Weighted Assets The minimum amount of Tier 1 Risk Based Capital, including capital conservation buffer, required for capital adequacy purposes under the regulatory framework for prompt corrective action. Tier 1 Capital Tier One Risk Based Capital Tier 1 Capital to Risk Weighted Assets Tier One Risk Based Capital to Risk Weighted Assets Total Capital (to Risk Weighted Assets) [Abstract] Capital [Abstract] Total Capital Ratio Required to be Well Capitalized Capital Required to be Well Capitalized to Risk Weighted Assets Minimum Capital Requirement, Total Capital to Risk Weighted Assets Capital Required for Capital Adequacy to Risk Weighted Assets Capital Conservation Buffer, Total Capital to Risk Weighted Assets Capital Conservation Buffer Total Capital to Risk Weighted Assets Capital conservation buffer required in excess of minimum capital requirements for total capital as defined by regulation. Minimum Capital Requirement Including Capital Conservation Buffer, Total Capital to Risk Weighted Assets Minimum Capital Requirement Including Capital Conservation Buffer for Total Capital to Risk Weighted Assets Minimum capital requirement including capital conservation buffer for Total Capital to Risk Weighted Assets as defined by regulation. Total Capital Capital Total Capital to Risk Weighted Assets Capital to Risk Weighted Assets Tier 1 Capital (to Average Assets) [Abstract] Tier One Leverage Capital [Abstract] Leverage Ratio Required to be Well Capitalized Tier One Leverage Capital Required to be Well Capitalized to Average Assets Minimum Capital Requirement, Tier 1 Capital to Average Assets Tier One Leverage Capital Required for Capital Adequacy to Average Assets Minimum Capital Requirements Including Capital Conservation Buffer, Tier 1 Capital to Average Assets Minimum Capital Requirements Including Capital Conservation Buffer, Tier One Capital to Average Assets The minimum amount of Tier 1 Leverage Capital, including capital conservation buffer, for capital adequacy purposes divided by average assets as defined in the regulations. Tier 1 Leverage Capital Tier One Leverage Capital Tier 1 Capital to Average Assets Tier One Leverage Capital to Average Assets Phased in Capital Conservation Buffer Phased in Capital Conservation Buffer Represents the phased in Capital Conservation Buffer at the period end. Fully Phased In Capital Conservation Buffer Fully Phased In Capital Conservation Buffer Represents the Capital Conservation Buffer once fully phased in. Schedule of Finite-Lived Intangible Assets by Major Class [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Core deposits premiums [Member] Core Deposits [Member] Other identifiable intangible assets [Member] Other Intangible Assets [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Finite-lived intangible assets, gross Finite-Lived Intangible Assets, Gross Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Finite-lived intangible assets, net Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2020 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2024 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Schedule of Goodwill [Table] Schedule of Goodwill [Table] Commercial [Member] Commercial [Member] Business segment-commercial customers. Consumer [Member] Consumer [Member] Business segment-consumer customers. Wealth Management [Member] Wealth Management [Member] Business segment-wealth management consulting customers. Funds Management and Other [Member] Funds Management and Other [Member] An operating segment that manages the overall liquidity needs and interest rate risk activities of the company from which it may earn revenues and incur expenses. Goodwill [Line Items] Goodwill [Line Items] Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, Beginning Balance Goodwill recognized during period Goodwill, Acquired During Period Adjustment Goodwill, Purchase Accounting Adjustments Goodwill, Ending Balance Disaggregation of Fees and Commissions Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block]