Significant Accounting Policies	9 Months Ended
Sep. 30, 2014
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	(1) Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements of BOK Financial Corporation (“BOK Financial” or “the Company”) have been prepared in accordance with accounting principles for interim financial information generally accepted in the United States and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. The unaudited consolidated financial statements include accounts of BOK Financial and its subsidiaries, principally BOKF, NA (“the Bank”), BOSC, Inc., The Milestone Group, Inc. and Cavanal Hill Investment Management Inc. Operating divisions of the Bank include Bank of Albuquerque, Bank of Arizona, Bank of Arkansas, Bank of Oklahoma, Bank of Texas, Colorado State Bank and Trust, Bank of Kansas City, BOK Financial Mortgage and the TransFund electronic funds network. Certain reclassifications have been made to conform to the current period presentation. The financial information should be read in conjunction with BOK Financial’s 2013 Form 10-K filed with the Securities and Exchange Commission, which contains audited financial statements. Amounts presented as of December 31, 2013 have been derived from the audited financial statements included in BOK Financial’s 2013 Form 10-K but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. Operating results for the nine-month period ended September 30, 2014 are not necessarily indicative of the results that may be expected for the year ending December 31, 2014. Newly Adopted and Pending Accounting Policies Financial Accounting Standards Board (“FASB”) FASB Accounting Standards Update No. 2013-08, Financial Services – Investment Companies (Topic 946): Amendments to the Scope, Measurement, and Disclosure Requirements ("ASU 2013-08") On June 7, 2013, the FASB issued ASU 2013-08 which amends the criteria an entity would need to meet to qualify as an investment company under ASC 946, Financial Services - Investment Companies. ASU 2013-08 also provides additional implementation guidance for the assessment and requires additional disclosures. ASU 2013-08 was effective prospectively during interim and annual periods beginning after December 15, 2013, with early adoption prohibited. The adoption of ASU 2013-08 did not have a material impact on the Company's consolidated financial statements. FASB Accounting Standards Update No. 2014-01, Accounting for Investments in Qualified Affordable Housing Projects ("ASU 2014-01") On January 15, 2014, the FASB issued ASU 2014-01 to simplify the amortization method an entity uses and modify the criteria to elect a measurement and presentation alternative, including the simplified amortization method, for certain investments in qualified affordable housing projects. This alternative permits the entity to present the investment's performance net of the related tax benefits as part of income tax expense. ASU 2014-01 is effective for the Company for interim and annual periods beginning after December 15, 2014. Early adoption is permitted. Adoption of ASU 2014-01 may affect income statement presentation, but otherwise is not expected to have a material impact on the Company's consolidated financial statements. FASB Accounting Standards Update No. 2014-04, Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans Upon Foreclosure ("ASU 2014-04") On January 17, 2014, the FASB issued ASU 2014-04 to clarify when an entity is considered to have obtained physical possession (from an in-substance possession or foreclosure) of a residential real estate property collateralizing a mortgage loan. Upon physical possession of such real property, an entity is required to reclassify the nonperforming mortgage loan to other real estate owned. ASU 2014-04 is effective for the Company for interim and annual periods beginning after December 15, 2014. Early adoption is permitted. Adoption of ASU 2014-04 is not expected to have a material impact on the Company's consolidated financial statements. FASB Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09") On May 28, 2014, the FASB issued ASU 2014-09 to clarify the principles for recognizing revenue by providing a more robust framework that will give greater consistency and comparability in revenue recognition practices. In the new framework, an entity recognizes revenue in an amount that reflects the consideration to which the entity expects to be entitled in exchange for goods or services. The new model requires the identification of performance obligations included in contracts with customers, a determination of the transaction price and an allocation of the price to those performance obligations. The entity recognizes revenue when performance obligations are satisfied. ASU 2014-09 is effective for the Company for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The Company is evaluating the impact the adoption of ASU 2014-09 will have on the Company's financial statements. FASB Accounting Standards Update No. 2014-14, Classification of Certain Government-Guaranteed Mortgage Loans Upon Foreclosure ("ASU 2014-14") On August 8, 2014, the FASB issued ASU 2014-14 to give greater consistency in the classification of government-guaranteed loans upon foreclosure. ASU 2014-14 applies to all loans that contain a government guarantee that is not separable from the loan or for which the creditor has both the intent and ability to recover a fixed amount under the guarantee by conveying the property to the guarantor. Upon foreclosure, the creditor should reclassify the mortgage loan to an other receivable that is separate from loans and should measure the receivable at the amount of the loan balance expected to be recovered from the guarantor. ASU 2014-14 is effective for the Company for interim and annual periods beginning after December 15, 2014. Early adoption is permitted if the entity has already adopted ASU 2014-14. As of September 30, 2014, approximately $47 million of real estate and other repossessed assets is expected to be reclassified from Real estate and other repossessed assets to Receivables on the balance sheet with adoption of ASC 2014-14.

(1) Significant Accounting Policies

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements of BOK Financial Corporation (“BOK Financial” or “the Company”) have been prepared in accordance with accounting principles for interim financial information generally accepted in the United States and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included.

The unaudited consolidated financial statements include accounts of BOK Financial and its subsidiaries, principally BOKF, NA (“the Bank”), BOSC, Inc., The Milestone Group, Inc. and Cavanal Hill Investment Management Inc. Operating divisions of the Bank include Bank of Albuquerque, Bank of Arizona, Bank of Arkansas, Bank of Oklahoma, Bank of Texas, Colorado State Bank and Trust, Bank of Kansas City, BOK Financial Mortgage and the TransFund electronic funds network.

Certain reclassifications have been made to conform to the current period presentation.

The financial information should be read in conjunction with BOK Financial’s 2013 Form 10-K filed with the Securities and Exchange Commission, which contains audited financial statements. Amounts presented as of December 31, 2013 have been derived from the audited financial statements included in BOK Financial’s 2013 Form 10-K but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. Operating results for the nine-month period ended September 30, 2014 are not necessarily indicative of the results that may be expected for the year ending December 31, 2014.

Newly Adopted and Pending Accounting Policies

Financial Accounting Standards Board (“FASB”)

FASB Accounting Standards Update No. 2013-08, Financial Services – Investment Companies (Topic 946): Amendments to the Scope, Measurement, and Disclosure Requirements ("ASU 2013-08")

On June 7, 2013, the FASB issued ASU 2013-08 which amends the criteria an entity would need to meet to qualify as an investment company under ASC 946, Financial Services - Investment Companies. ASU 2013-08 also provides additional implementation guidance for the assessment and requires additional disclosures. ASU 2013-08 was effective prospectively during interim and annual periods beginning after December 15, 2013, with early adoption prohibited. The adoption of ASU 2013-08 did not have a material impact on the Company's consolidated financial statements.

FASB Accounting Standards Update No. 2014-01, Accounting for Investments in Qualified Affordable Housing Projects ("ASU 2014-01")

On January 15, 2014, the FASB issued ASU 2014-01 to simplify the amortization method an entity uses and modify the criteria to elect a measurement and presentation alternative, including the simplified amortization method, for certain investments in qualified affordable housing projects. This alternative permits the entity to present the investment's performance net of the related tax benefits as part of income tax expense. ASU 2014-01 is effective for the Company for interim and annual periods beginning after December 15, 2014. Early adoption is permitted. Adoption of ASU 2014-01 may affect income statement presentation, but otherwise is not expected to have a material impact on the Company's consolidated financial statements.

FASB Accounting Standards Update No. 2014-04, Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans Upon Foreclosure ("ASU 2014-04")

On January 17, 2014, the FASB issued ASU 2014-04 to clarify when an entity is considered to have obtained physical possession (from an in-substance possession or foreclosure) of a residential real estate property collateralizing a mortgage loan. Upon physical possession of such real property, an entity is required to reclassify the nonperforming mortgage loan to other real estate owned. ASU 2014-04 is effective for the Company for interim and annual periods beginning after December 15, 2014. Early adoption is permitted. Adoption of ASU 2014-04 is not expected to have a material impact on the Company's consolidated financial statements.

FASB Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09")

On May 28, 2014, the FASB issued ASU 2014-09 to clarify the principles for recognizing revenue by providing a more robust framework that will give greater consistency and comparability in revenue recognition practices. In the new framework, an entity recognizes revenue in an amount that reflects the consideration to which the entity expects to be entitled in exchange for goods or services. The new model requires the identification of performance obligations included in contracts with customers, a determination of the transaction price and an allocation of the price to those performance obligations. The entity recognizes revenue when performance obligations are satisfied. ASU 2014-09 is effective for the Company for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The Company is evaluating the impact the adoption of ASU 2014-09 will have on the Company's financial statements.

FASB Accounting Standards Update No. 2014-14, Classification of Certain Government-Guaranteed Mortgage Loans Upon Foreclosure ("ASU 2014-14")

On August 8, 2014, the FASB issued ASU 2014-14 to give greater consistency in the classification of government-guaranteed loans upon foreclosure. ASU 2014-14 applies to all loans that contain a government guarantee that is not separable from the loan or for which the creditor has both the intent and ability to recover a fixed amount under the guarantee by conveying the property to the guarantor. Upon foreclosure, the creditor should reclassify the mortgage loan to an other receivable that is separate from loans and should measure the receivable at the amount of the loan balance expected to be recovered from the guarantor. ASU 2014-14 is effective for the Company for interim and annual periods beginning after December 15, 2014. Early adoption is permitted if the entity has already adopted ASU 2014-14. As of September 30, 2014, approximately $47 million of real estate and other repossessed assets is expected to be reclassified from Real estate and other repossessed assets to Receivables on the balance sheet with adoption of ASC 2014-14.