Commitments and Contingent Liabilities	6 Months Ended
Jun. 30, 2011
Commitments and Contingent Liabilities [Abstract]
Commitments and Contingent Liabilities	(7) Commitments and Contingent Liabilities BOSC, Inc. has been joined as a defendant in a putative class action brought on behalf of unit holders of SemGroup Energy Partners, LP in the United States District Court for the Northern District of Oklahoma. The lawsuit is brought pursuant to Sections 11 and 12(a)(2) of the Securities Act of 1933 against all of the underwriters of issuances of partnership units in the Initial Public Offering in July 2007 and in a Secondary Offering in January 2008. BOSC underwrote $6.25 million of units in the Initial Public Offering. BOSC was not an underwriter in the Secondary Offering. Counsel for BOSC believes BOSC has valid defenses to the claims asserted in the litigation. A definitive settlement agreement among the issuer, the underwriters, and all parties to the litigation has been reached at no material loss to the Company. The definitive agreement has been preliminarily approved by the Court and is set for hearing for final approval. In 2010, Bank of Oklahoma, National Association, was named as a defendant in three putative class actions alleging that the manner in which the bank posted charges to its consumer deposit accounts breached an implied obligation of good faith and fair dealing and violates the Oklahoma Consumer Protection Act. The actions also allege that the manner in which the bank posted charges to it consumer demand deposit accounts is unconscionable, constitutes conversion and unjustly enriches the bank. Two of the actions are pending in the District Court of Tulsa County. The third action, originally brought in the United State District Court for the Western District of Oklahoma, has been transferred to Multi-District Litigation in the Southern District of Florida. Each of the three actions seeks to establish a class consisting of all consumer customers of the bank. The amount claimed by the plaintiffs has not been determined, but could be material. Management has been advised by counsel that, in its opinion, the Company's overdraft policies meet all requirement of law and the Bank has substantial defenses to the claims. Based on currently available information, management has established an accrual within a reasonable range of probable losses and anticipates the claims will be resolved without material loss to the Company. As a member of Visa, BOK Financial is obligated for a proportionate share of certain covered litigation losses incurred by Visa under a retrospective responsibility plan. A contingent liability was recognized for the Company's share of Visa' covered litigation liabilities. The contingent liability totaled $774 thousand at June 30, 2011. Visa funded an escrow account to cover litigation claims, including covered litigation losses under the retrospective responsibility plan, with proceeds from its initial public offering in 2008 and from available cash. BOK Financial recognized a $774 thousand receivable for its proportionate share of this escrow account. BOK Financial currently owns 251,837 Visa Class B shares which are convertible into Visa Class A shares at the later of three years after the date of Visa's initial public offering or the final settlement of all covered litigation. The current exchange rate is approximately 0.4881 Class A shares for each Class B share. However, the Company's Class B shares may be diluted in the future if the escrow fund is not adequate to cover future covered litigation costs. Therefore, no value has been currently assigned to the Class B shares and no value may be assigned until the Class B shares are converted into a known number of Class A shares. At June 30, 2011, Cavanal Hill Funds' assets included $1.0 billion of U.S. Treasury, $863 million of cash management and $337 million of tax-free money market funds. Assets of these funds consist of highly-rated, short-term obligations of the U.S. Treasury, corporate issuers and U.S. states and municipalities. The net asset value of units in these funds was $1.00 at June 30, 2011. An investment in these funds is not insured by the Federal Deposit Insurance Corporation or guaranteed by BOK Financial or any of its subsidiaries. BOK Financial may, but is not obligated to purchase assets from these funds to maintain the net asset value at $1.00. No assets were purchased from the funds in 2011 or 2010. Cottonwood Valley Ventures, Inc. (“CVV, Inc.”), an indirectly wholly-owned subsidiary of BOK Financial, is being audited by the Oklahoma Tax Commission (“OTC”) for tax years 2007 through 2009. CVV, Inc. is a qualified venture capital company under the applicable Oklahoma statute. As authorized by the statute, CVV, Inc. guarantees transferable Oklahoma state income tax credits by providing direct debt financing to private companies which qualify as statutory business ventures. Due to certain statutory limitations on utilization of such credits, CVV, Inc. must sell the majority of the credits to provide the economic incentives provided for by the statute. In the event that the OTC disallows any of the credits, CVV, Inc. would be required to indemnify purchasers for the tax credits disallowed. Management does not anticipate that this audit will have a material adverse impact to the financial statements. BOKF Equity, LLC, an indirect wholly-owned subsidiary, is the general partner of two consolidated private equity funds (“the Funds”). The Funds provide alternative investment opportunities to certain customers, some of which are related parties, through unaffiliated limited partnerships. These unaffiliated limited partnerships generally invest in distressed assets, asset buy-outs or venture capital companies. At June 30, 2011, the Funds' assets, included in Other assets on the Consolidated Balance Sheets, totaled $28 million. The Funds have no debt. The general partner has contingent obligations to make additional investments totaling $14 million at June 30, 2011, substantially all of which are offset by limited partner commitments. The Company does not accrue its contingent liability to fund investments. The Company agreed to guarantee rents totaling $28.7 million through September of 2017 to the City of Tulsa (“City”) as owner of a building immediately adjacent to the Bank's main office for space currently rented by third-party tenants in the building. All rent payments are current. Remaining guaranteed rents totaled $18.6 million at June 30, 2011. Current leases expire or are subject to lessee termination options at various dates in 2012 and 2014. Our obligation under the agreement would be affected by lessee decisions to exercise these options. In return for this guarantee, the Company will receive 80% of net cash flow as defined in an agreement with the City through September 2017 from rental of space that was vacant at the inception of the agreement. Approximately 42 thousand square feet of this additional space has been rented to outside parties since the date of the agreement. The maximum amount that the Company may receive under this agreement is $4.5 million. In the ordinary course of business, BOK Financial and its subsidiaries are subject to legal actions and complaints. Management believes, based upon the opinion of counsel, that the actions and liability or loss, if any, resulting from the final outcomes of the proceedings, will not have a material effect on the Company's financial condition, results of operations or cash flows.

(7) Commitments and Contingent Liabilities

BOSC, Inc. has been joined as a defendant in a putative class action brought on behalf of unit holders of SemGroup Energy Partners, LP in the United States District Court for the Northern District of Oklahoma. The lawsuit is brought pursuant to Sections 11 and 12(a)(2) of the Securities Act of 1933 against all of the underwriters of issuances of partnership units in the Initial Public Offering in July 2007 and in a Secondary Offering in January 2008. BOSC underwrote $6.25 million of units in the Initial Public Offering. BOSC was not an underwriter in the Secondary Offering. Counsel for BOSC believes BOSC has valid defenses to the claims asserted in the litigation. A definitive settlement agreement among the issuer, the underwriters, and all parties to the litigation has been reached at no material loss to the Company. The definitive agreement has been preliminarily approved by the Court and is set for hearing for final approval.

In 2010, Bank of Oklahoma, National Association, was named as a defendant in three putative class actions alleging that the manner in which the bank posted charges to its consumer deposit accounts breached an implied obligation of good faith and fair dealing and violates the Oklahoma Consumer Protection Act. The actions also allege that the manner in which the bank posted charges to it consumer demand deposit accounts is unconscionable, constitutes conversion and unjustly enriches the bank. Two of the actions are pending in the District Court of Tulsa County. The third action, originally brought in the United State District Court for the Western District of Oklahoma, has been transferred to Multi-District Litigation in the Southern District of Florida. Each of the three actions seeks to establish a class consisting of all consumer customers of the bank. The amount claimed by the plaintiffs has not been determined, but could be material. Management has been advised by counsel that, in its opinion, the Company's overdraft policies meet all requirement of law and the Bank has substantial defenses to the claims. Based on currently available information, management has established an accrual within a reasonable range of probable losses and anticipates the claims will be resolved without material loss to the Company.

As a member of Visa, BOK Financial is obligated for a proportionate share of certain covered litigation losses incurred by Visa under a retrospective responsibility plan. A contingent liability was recognized for the Company's share of Visa' covered litigation liabilities. The contingent liability totaled $774 thousand at June 30, 2011. Visa funded an escrow account to cover litigation claims, including covered litigation losses under the retrospective responsibility plan, with proceeds from its initial public offering in 2008 and from available cash. BOK Financial recognized a $774 thousand receivable for its proportionate share of this escrow account.

BOK Financial currently owns 251,837 Visa Class B shares which are convertible into Visa Class A shares at the later of three years after the date of Visa's initial public offering or the final settlement of all covered litigation. The current exchange rate is approximately 0.4881 Class A shares for each Class B share. However, the Company's Class B shares may be diluted in the future if the escrow fund is not adequate to cover future covered litigation costs. Therefore, no value has been currently assigned to the Class B shares and no value may be assigned until the Class B shares are converted into a known number of Class A shares.

At June 30, 2011, Cavanal Hill Funds' assets included $1.0 billion of U.S. Treasury, $863 million of cash management and $337 million of tax-free money market funds. Assets of these funds consist of highly-rated, short-term obligations of the U.S. Treasury, corporate issuers and U.S. states and municipalities. The net asset value of units in these funds was $1.00 at June 30, 2011. An investment in these funds is not insured by the Federal Deposit Insurance Corporation or guaranteed by BOK Financial or any of its subsidiaries. BOK Financial may, but is not obligated to purchase assets from these funds to maintain the net asset value at $1.00. No assets were purchased from the funds in 2011 or 2010.

Cottonwood Valley Ventures, Inc. (“CVV, Inc.”), an indirectly wholly-owned subsidiary of BOK Financial, is being audited by the Oklahoma Tax Commission (“OTC”) for tax years 2007 through 2009. CVV, Inc. is a qualified venture capital company under the applicable Oklahoma statute. As authorized by the statute, CVV, Inc. guarantees transferable Oklahoma state income tax credits by providing direct debt financing to private companies which qualify as statutory business ventures. Due to certain statutory limitations on utilization of such credits, CVV, Inc. must sell the majority of the credits to provide the economic incentives provided for by the statute. In the event that the OTC disallows any of the credits, CVV, Inc. would be required to indemnify purchasers for the tax credits disallowed. Management does not anticipate that this audit will have a material adverse impact to the financial statements.

BOKF Equity, LLC, an indirect wholly-owned subsidiary, is the general partner of two consolidated private equity funds (“the Funds”). The Funds provide alternative investment opportunities to certain customers, some of which are related parties, through unaffiliated limited partnerships. These unaffiliated limited partnerships generally invest in distressed assets, asset buy-outs or venture capital companies. At June 30, 2011, the Funds' assets, included in Other assets on the Consolidated Balance Sheets, totaled $28 million. The Funds have no debt. The general partner has contingent obligations to make additional investments totaling $14 million at June 30, 2011, substantially all of which are offset by limited partner commitments. The Company does not accrue its contingent liability to fund investments.

The Company agreed to guarantee rents totaling $28.7 million through September of 2017 to the City of Tulsa (“City”) as owner of a building immediately adjacent to the Bank's main office for space currently rented by third-party tenants in the building. All rent payments are current. Remaining guaranteed rents totaled $18.6 million at June 30, 2011. Current leases expire or are subject to lessee termination options at various dates in 2012 and 2014. Our obligation under the agreement would be affected by lessee decisions to exercise these options. In return for this guarantee, the Company will receive 80% of net cash flow as defined in an agreement with the City through September 2017 from rental of space that was vacant at the inception of the agreement. Approximately 42 thousand square feet of this additional space has been rented to outside parties since the date of the agreement. The maximum amount that the Company may receive under this agreement is $4.5 million.

In the ordinary course of business, BOK Financial and its subsidiaries are subject to legal actions and complaints. Management believes, based upon the opinion of counsel, that the actions and liability or loss, if any, resulting from the final outcomes of the proceedings, will not have a material effect on the Company's financial condition, results of operations or cash flows.