XML 48 R38.htm IDEA: XBRL DOCUMENT
v3.20.2

Derivatives, Fair Value of Derivatives Contracts (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derviative contracts, net of cash collateral, Assets, Fair value | $ 593,568 |  | $ 323,375 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 446,328 |  | 251,128 |
Not Designated as Hedging Instrument [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 73,085,428 | [1] | 75,917,378 | [2]
Derivative Liabilities, Notional | 72,386,971 | [1] | 70,400,171 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 1,099,436 |  | 549,555 |
Derivative Assets, Netting Adjustments | (409,255) |  | (225,482) |
Derivative Assets, Net Fair Value Before Cash Collateral | 690,181 |  | 324,073 |
Derivative Assets, Cash Collateral | (96,613) |  | (698) |
Derviative contracts, net of cash collateral, Assets, Fair value | 593,568 |  | 323,375 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 1,055,185 |  | 528,921 |
Derivative Liabilities, Netting Adjustments | (409,255) |  | (225,482) |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 645,930 |  | 303,439 |
Derivative Liabilities, Cash Collateral | (199,602) |  | (52,311) |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 446,328 |  | 251,128 |
Not Designated as Hedging Instrument [Member] | Total customer risk management programs |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 7,060,324 | [1] | 4,927,266 | [2]
Derivative Liabilities, Notional | 6,855,256 | [1] | 4,875,382 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 844,903 |  | 411,768 |
Derivative Assets, Netting Adjustments | (229,540) |  | (109,452) |
Derivative Assets, Net Fair Value Before Cash Collateral | 615,363 |  | 302,316 |
Derivative Assets, Cash Collateral | (92,789) |  | (698) |
Derviative contracts, net of cash collateral, Assets, Fair value | 522,574 |  | 301,618 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 818,517 |  | 400,265 |
Derivative Liabilities, Netting Adjustments | (229,540) |  | (109,452) |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 588,977 |  | 290,813 |
Derivative Liabilities, Cash Collateral | (160,344) |  | (51,448) |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 428,633 |  | 239,365 |
Not Designated as Hedging Instrument [Member] | Interest rate contracts [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 3,179,414 | [1] | 2,464,478 | [2]
Derivative Liabilities, Notional | 3,179,414 | [1] | 2,464,478 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 132,320 |  | 49,100 |
Derivative Assets, Netting Adjustments | (107) |  | (1,839) |
Derivative Assets, Net Fair Value Before Cash Collateral | 132,213 |  | 47,261 |
Derivative Assets, Cash Collateral | 0 |  | 0 |
Derviative contracts, net of cash collateral, Assets, Fair value | 132,213 |  | 47,261 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 132,689 |  | 49,194 |
Derivative Liabilities, Netting Adjustments | (107) |  | (1,839) |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 132,582 |  | 47,355 |
Derivative Liabilities, Cash Collateral | (121,212) |  | (43,932) |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 11,370 |  | 3,423 |
Not Designated as Hedging Instrument [Member] | Energy contracts [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 3,482,226 | [1] | 2,151,096 | [2]
Derivative Liabilities, Notional | 3,277,670 | [1] | 2,105,391 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 400,646 |  | 144,906 |
Derivative Assets, Netting Adjustments | (229,433) |  | (107,591) |
Derivative Assets, Net Fair Value Before Cash Collateral | 171,213 |  | 37,315 |
Derivative Assets, Cash Collateral | (92,170) |  | (38) |
Derviative contracts, net of cash collateral, Assets, Fair value | 79,043 |  | 37,277 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 374,542 |  | 139,311 |
Derivative Liabilities, Netting Adjustments | (229,433) |  | (107,591) |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 145,109 |  | 31,720 |
Derivative Liabilities, Cash Collateral | (37,276) |  | (6,031) |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 107,833 |  | 25,689 |
Not Designated as Hedging Instrument [Member] | Agricultural contracts [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 13,611 | [1] | 16,118 | [2]
Derivative Liabilities, Notional | 13,627 | [1] | 16,139 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 1,870 |  | 1,522 |
Derivative Assets, Netting Adjustments | 0 |  | (22) |
Derivative Assets, Net Fair Value Before Cash Collateral | 1,870 |  | 1,500 |
Derivative Assets, Cash Collateral | 0 |  | 0 |
Derviative contracts, net of cash collateral, Assets, Fair value | 1,870 |  | 1,500 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 1,856 |  | 1,507 |
Derivative Liabilities, Netting Adjustments | 0 |  | (22) |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 1,856 |  | 1,485 |
Derivative Liabilities, Cash Collateral | (1,856) |  | (1,485) |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 0 |  | 0 |
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 311,626 | [1] | 214,119 | [2]
Derivative Liabilities, Notional | 311,098 | [1] | 207,919 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 309,130 |  | 213,007 |
Derivative Assets, Netting Adjustments | 0 |  | 0 |
Derivative Assets, Net Fair Value Before Cash Collateral | 309,130 |  | 213,007 |
Derivative Assets, Cash Collateral | (400) |  | 0 |
Derviative contracts, net of cash collateral, Assets, Fair value | 308,730 |  | 213,007 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 308,493 |  | 207,020 |
Derivative Liabilities, Netting Adjustments | 0 |  | 0 |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 308,493 |  | 207,020 |
Derivative Liabilities, Cash Collateral | 0 |  | 0 |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 308,493 |  | 207,020 |
Not Designated as Hedging Instrument [Member] | Equity option contracts [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 73,447 | [1] | 81,455 | [2]
Derivative Liabilities, Notional | 73,447 | [1] | 81,455 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 937 |  | 3,233 |
Derivative Assets, Netting Adjustments | 0 |  | 0 |
Derivative Assets, Net Fair Value Before Cash Collateral | 937 |  | 3,233 |
Derivative Assets, Cash Collateral | (219) |  | (660) |
Derviative contracts, net of cash collateral, Assets, Fair value | 718 |  | 2,573 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 937 |  | 3,233 |
Derivative Liabilities, Netting Adjustments | 0 |  | 0 |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 937 |  | 3,233 |
Derivative Liabilities, Cash Collateral | 0 |  | 0 |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 937 |  | 3,233 |
Not Designated as Hedging Instrument [Member] | Trading [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 65,290,962 | [1] | 69,721,932 | [2]
Derivative Liabilities, Notional | 64,972,263 | [1] | 65,144,388 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 235,176 |  | 131,561 |
Derivative Assets, Netting Adjustments | (173,680) |  | (115,949) |
Derivative Assets, Net Fair Value Before Cash Collateral | 61,496 |  | 15,612 |
Derivative Assets, Cash Collateral | (3,824) |  | 0 |
Derviative contracts, net of cash collateral, Assets, Fair value | 57,672 |  | 15,612 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 229,013 |  | 125,535 |
Derivative Liabilities, Netting Adjustments | (173,680) |  | (115,949) |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 55,333 |  | 9,586 |
Derivative Liabilities, Cash Collateral | (38,999) |  | 0 |
Derivative Liabilities, Fair Value, Net of Cash Collateral | 16,334 |  | 9,586 |
Not Designated as Hedging Instrument [Member] | Internal risk management programs [Member] |  |  |  |
Notional Amount of Derivatives [Abstract] |  |  |  |
Derivative Assets, Notional | 734,142 | [1] | 1,268,180 | [2]
Derivative Liabilities, Notional | 559,452 | [1] | 380,401 | [2]
Derivative Assets, Fair Value, Net [Abstract] |  |  |  |
Derivative Assets, Gross Fair Value | 19,357 |  | 6,226 |
Derivative Assets, Netting Adjustments | (6,035) |  | (81) |
Derivative Assets, Net Fair Value Before Cash Collateral | 13,322 |  | 6,145 |
Derivative Assets, Cash Collateral | 0 |  | 0 |
Derviative contracts, net of cash collateral, Assets, Fair value | 13,322 |  | 6,145 |
Derivative Liabilities, Fair Value, Net [Abstract] |  |  |  |
Derivative Liabilities, Gross Fair Value | 7,655 |  | 3,121 |
Derivative Liabilities, Netting Adjustments | (6,035) |  | (81) |
Derivative Liabilities, Net Fair Value Before Cash Collateral | 1,620 |  | 3,040 |
Derivative Liabilities, Cash Collateral | (259) |  | (863) |
Derivative Liabilities, Fair Value, Net of Cash Collateral | $ 1,361 |  | $ 2,177 |
[1] | Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract.
[2] | Notional amounts for commodity contracts are converted into dollar-equivalent amounts based on dollar prices at the inception of the contract.

X
- Definition Represents amount of gross derivative asset positions offset by gross derivate liability due to enforceable master netting or similar agreements. + References No definition available. + Details
Name: | bokf_DerivativeAssetNettingAdjustments
Namespace Prefix: | bokf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents net derivative assets before offsetting the obligation to return cash collateral under a master netting or similar arrangement. + References No definition available. + Details
Name: | bokf_DerivativeAssetsNetFairValueBeforeCashCollateral
Namespace Prefix: | bokf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents net derivative liability before consideration of right to reclasim cash collateral under master netting or similar arrangements. + References No definition available. + Details
Name: | bokf_DerivativeLiabilityNetFairValueBeforeCashCollateral
Namespace Prefix: | bokf_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents amount of gross derivative liability positions offset by gross derivative asset positions due to enforceable master netting or similar arrangements. + References No definition available. + Details
Name: | bokf_DerivativeLiabilityNettingAdjustments
Namespace Prefix: | bokf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958 + Details
Name: | us-gaap_DerivativeAssetCollateralObligationToReturnCashOffset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DerivativeAssetFairValueNetAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payments on the derivative asset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeAssetNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DerivativeLiabilityFairValueNetAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payments on the derivative liability. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeLiabilityNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_NotionalAmountOfDerivativesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=bokf_CustomerRiskManagementProgramsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_EnergyRelatedDerivativeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=bokf_AgriculturalContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_EquitySwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=bokf_TradingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=bokf_InternalRiskManagementProgramsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |