Commitments and Contingent Liabilities	3 Months Ended
Mar. 31, 2026
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Commitments and Contingent Liabilities Litigation Contingencies 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’s covered litigation liabilities. 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. On January 23, 2024, Visa, Inc. stockholders approved an exchange offer which provided holders of Class B-1 shares an option to convert up to 50% of its Class B-1 shares to Visa Class B-2 shares and Visa C shares, and subsequently to freely transferable Visa A common shares, subject to certain restrictions and holding period requirements (the "2024 Exchange Offer"). BOK Financial currently owns 126,116 Visa Class B-2 shares. As a condition of participating in the 2024 Exchange Offer, the Company entered into a Makewhole Agreement (the "2024 Makewhole Agreement") with Visa that provides for cash payments to Visa to the extent, if any, that future adjustments to the conversion ratio for the Visa Class B-2 common stock to Class A common stock cause such ratio to fall below zero. Currently, Visa Class B-2 common stock is convertible under certain circumstances into Visa’s publicly traded Class A common stock at a rate of 1.5075 shares of Class A common stock for each Visa B-2 share, subject to adjustment. Changes to the conversion ratio occur when Visa deposits funds into a litigation escrow fund established by Visa to pay settlements for certain covered litigation that pre-dated Visa’s initial public offering, for which Visa has been effectively indemnified by Visa USA members through reductions to the conversion ratio for its Class B-1 common stock. The purpose of the 2024 Makewhole Agreement is to preserve the economic benefit of these adjustments to the Class B-1 conversion ratio for the benefit of Visa’s Class A and Class C common stockholders following the exchange. As further described in Visa’s related Issuer Tender Offer Statement on Schedule TO and Prospectus, each dated April 8, 2024 and publicly filed with the U.S. SEC, both the 2024 Makewhole Agreement and the related escrow fund and transfer restrictions on Visa’s Class B-1 common stock and the Class B-2 common stock will terminate whenever the covered litigation is ultimately resolved, at which future date outstanding shares of Visa Class B-2 common stock will be convertible into shares of its Class A common stock at the then-applicable conversion ratio. On April 13, 2026, Visa, Inc. initiated its first successive Exchange Offer (the "Exchange Offer") for holders of Class B-1 or Class B-2 shares (collectively, "Class B shares") to exchange Class B shares for a combination of Visa Class B-3 common shares and Visa Class C common shares, subject to holding periods and certain other conditions contained in the Exchange Offer. The Exchange Offer opened on April 13, 2026, and is scheduled to expire at the end of the day on May 8, 2026. The Company tendered its Class B-2 Visa shares under the Exchange Offer and expects to receive 63,058 newly issued Class B-3 shares subject to the same restrictions on transfer and conversion that applied to Class B-2 shares. The Company also expects to receive 23,760 Class C shares which are convertible into 95,040 Visa Class A common shares upon expiration of the Exchange Offer. Receipt of such shares is contingent on Visa's acceptance of the tendered Class B-2 shares. The Company also entered into a Makewhole Agreement (the "2026 Makewhole Agreement"). As further described in Visa’s related Issuer Tender Offer Statement on Schedule TO and Prospectus, each dated April 13, 2026 and publicly filed with the U. S. Securities and Exchange Commission, holders of Visa B shares who are subject to multiple Makewhole Agreements are only obligated to reimburse Visa under a Makewhole Agreement that corresponds to one class of Class B common stock at any given time. Both the 2026 and 2024 Makewhole Agreements and the related escrow fund and transfer restrictions on Visa’s Class B shares will terminate whenever the covered litigation is ultimately resolved, at which future date outstanding shares of Visa Class B shares will be convertible into shares of its Class A common stock at the then-applicable conversion ratio. Conversion of Class B shares would not reduce our proportionate share of the covered litigation losses which may dilute our remaining Class B shares if the escrow fund is not adequate to cover final litigation costs. On June 24, 2015, BOKF, NA received a complaint that an employee had colluded with a bond issuer and an individual in misusing revenues pledged to municipal bonds for which BOKF, NA served as trustee under the bond indenture. The Company conducted an investigation and concluded that employees in one of its Corporate Trust offices had, with respect to a single group of affiliated bond issuances, violated Company policies and procedures. The relationship manager was terminated. The Company reported the circumstances to, and cooperated with an investigation by, the SEC. On September 7, 2016, BOKF, NA agreed to, and the SEC entered, a consent order finding that BOKF, NA had violated Section 17(a) of the Securities Act of 1933 and Section 10(b) of the Securities Exchange Act and required BOKF, NA to disgorge $1,067,721 of fees and pay a civil penalty of $600,000. BOKF, NA disgorged the fees and paid the penalty. On August 26, 2016, BOKF, NA was sued in the United States District Court for New Jersey by two bondholders in a putative class action alleging BOKF, NA participated in the fraudulent sale of securities by the principals. On March 12, 2026, the Court lifted the stay for the limited purpose of allowing Defendants to file dispositive Motions which are due May 7, 2026. On December 28, 2015, in an action brought by the SEC, the New Jersey District Court entered a Consent Judgment against the principals involved in issuing the bonds. On January 8, 2020, the Court entered Final Judgment against the principal individual and his wife for $36,805,051 in principal amount and $10,937,831 in pre-judgment interest. The sale of all remaining collateral securing payment of the bonds has occurred and approximately $29 million remains outstanding. The SEC continues to aggressively pursue collection of the judgment. If the individual principal and his wife cannot pay the bonds, a bondholder loss could become probable. Management has been advised by counsel that BOKF, NA has valid defenses to claims of bondholders and that no loss to the Company is probable. No provision for losses has been made at this time. 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. Alternative Investment Commitments The Company invests in several tax credit entities and other funds as permitted by banking regulations. Consolidation of these investments is based on the variable interest model. At March 31, 2026, the Company had $449 million in interests in various alternative investments generally consisting of unconsolidated limited partnership interests in entities for which investment return is in the form of low income housing tax credits or other investments in merchant banking activities. These investments are recognized in Other assets on the Consolidated Balance Sheets. This investment balance also includes $134 million of unfunded commitments included in Other liabilities on the Consolidated Balance Sheets.

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’s covered litigation liabilities. 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 currently owns 126,116 Visa Class B-2 shares. As a condition of participating in the 2024 Exchange Offer, the Company entered into a Makewhole Agreement (the "2024 Makewhole Agreement") with Visa that provides for cash payments to Visa to the extent, if any, that future adjustments to the conversion ratio for the Visa Class B-2 common stock to Class A common stock cause such ratio to fall below zero. Currently, Visa Class B-2 common stock is convertible under certain circumstances into Visa’s publicly traded Class A common stock at a rate of 1.5075 shares of Class A common stock for each Visa B-2 share, subject to adjustment. Changes to the conversion ratio occur when Visa deposits funds into a litigation escrow fund established by Visa to pay settlements for certain covered litigation that pre-dated Visa’s initial public offering, for which Visa has been effectively indemnified by Visa USA members through reductions to the conversion ratio for its Class B-1 common stock. The purpose of the 2024 Makewhole Agreement is to preserve the economic benefit of these adjustments to the Class B-1 conversion ratio for the benefit of Visa’s Class A and Class C common stockholders following the exchange. As further described in Visa’s related Issuer Tender Offer Statement on Schedule TO and Prospectus, each dated April 8, 2024 and publicly filed with the U.S. SEC, both the 2024 Makewhole Agreement and the related escrow fund and transfer restrictions on Visa’s Class B-1 common stock and the Class B-2 common stock will terminate whenever the covered litigation is ultimately resolved, at which future date outstanding shares of Visa Class B-2 common stock will be convertible into shares of its Class A common stock at the then-applicable conversion ratio.

On April 13, 2026, Visa, Inc. initiated its first successive Exchange Offer (the "Exchange Offer") for holders of Class B-1 or Class B-2 shares (collectively, "Class B shares") to exchange Class B shares for a combination of Visa Class B-3 common shares and Visa Class C common shares, subject to holding periods and certain other conditions contained in the Exchange Offer. The Exchange Offer opened on April 13, 2026, and is scheduled to expire at the end of the day on May 8, 2026. The Company tendered its Class B-2 Visa shares under the Exchange Offer and expects to receive 63,058 newly issued Class B-3 shares subject to the same restrictions on transfer and conversion that applied to Class B-2 shares. The Company also expects to receive 23,760 Class C shares which are convertible into 95,040 Visa Class A common shares upon expiration of the Exchange Offer. Receipt of such shares is contingent on Visa's acceptance of the tendered Class B-2 shares. The Company also entered into a Makewhole Agreement (the "2026 Makewhole Agreement"). As further described in Visa’s related Issuer Tender Offer Statement on Schedule TO and Prospectus, each dated April 13, 2026 and publicly filed with the U. S. Securities and Exchange Commission, holders of Visa B shares who are subject to multiple Makewhole Agreements are only obligated to reimburse Visa under a Makewhole Agreement that corresponds to one class of Class B common stock at any given time. Both the 2026 and 2024 Makewhole Agreements and the related escrow fund and transfer restrictions on Visa’s Class B shares will terminate whenever the covered litigation is ultimately resolved, at which future date outstanding shares of Visa Class B shares will be convertible into shares of its Class A common stock at the then-applicable conversion ratio. Conversion of Class B shares would not reduce our proportionate share of the covered litigation losses which may dilute our remaining Class B shares if the escrow fund is not adequate to cover final litigation costs.

On June 24, 2015, BOKF, NA received a complaint that an employee had colluded with a bond issuer and an individual in misusing revenues pledged to municipal bonds for which BOKF, NA served as trustee under the bond indenture. The Company conducted an investigation and concluded that employees in one of its Corporate Trust offices had, with respect to a single group of affiliated bond issuances, violated Company policies and procedures. The relationship manager was terminated. The Company reported the circumstances to, and cooperated with an investigation by, the SEC. On September 7, 2016, BOKF, NA agreed to, and the SEC entered, a consent order finding that BOKF, NA had violated Section 17(a) of the Securities Act of 1933 and Section 10(b) of the Securities Exchange Act and required BOKF, NA to disgorge $1,067,721 of fees and pay a civil penalty of $600,000. BOKF, NA disgorged the fees and paid the penalty. On August 26, 2016, BOKF, NA was sued in the United States District Court for New Jersey by two bondholders in a putative class action alleging BOKF, NA participated in the fraudulent sale of securities by the principals. On March 12, 2026, the Court lifted the stay for the limited purpose of allowing Defendants to file dispositive Motions which are due May 7, 2026.

On December 28, 2015, in an action brought by the SEC, the New Jersey District Court entered a Consent Judgment against the principals involved in issuing the bonds. On January 8, 2020, the Court entered Final Judgment against the principal individual and his wife for $36,805,051 in principal amount and $10,937,831 in pre-judgment interest. The sale of all remaining collateral securing payment of the bonds has occurred and approximately $29 million remains outstanding. The SEC continues to aggressively pursue collection of the judgment. If the individual principal and his wife cannot pay the bonds, a bondholder loss could become probable. Management has been advised by counsel that BOKF, NA has valid defenses to claims of bondholders and that no loss to the Company is probable. No provision for losses has been made at this time.

At March 31, 2026, the Company had $449 million in interests in various alternative investments generally consisting of unconsolidated limited partnership interests in entities for which investment return is in the form of low income housing tax credits or other investments in merchant banking activities. These investments are recognized in Other assets on the Consolidated Balance Sheets. This investment balance also includes $134 million of unfunded commitments included in Other liabilities on the Consolidated Balance Sheets.