Other Borrowed Funds (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019
Other Borrowed Funds [Line Items]
Balance		$ 2,494,428		$ 3,821,361	$ 8,621,328
Average Balance		$ 5,062,621		$ 8,570,959	$ 10,261,592
Rate		0.56%		0.82%	2.37%
Other borrowed funds, Maturities [Abstract]
2022		$ 2,343,341
2023		3,378
2024		3,498
2025		3,622
2026		3,752
Thereafter		136,837
Funds purchased [Member]
Other Borrowed Funds [Line Items]
Balance		$ 199,513		$ 769,365	$ 3,390,528
Rate		0.05%		0.05%	1.53%
Average Balance		$ 543,183		$ 2,045,795	$ 2,438,376
Rate		0.46%		0.58%	2.08%
Maximum Outstanding At Any Month End		$ 542,465		$ 3,311,938	$ 3,390,528
Repurchase agreements [Member]
Other Borrowed Funds [Line Items]
Balance		$ 2,126,936		$ 893,021	$ 427,822
Rate		0.08%		0.09%	0.50%
Average Balance		$ 1,695,519		$ 1,589,746	$ 399,785
Rate		0.33%		0.24%	0.57%
Maximum Outstanding At Any Month End		$ 2,920,728		$ 3,230,097	$ 427,822
Other Borrowings [Member]
Other Borrowed Funds [Line Items]
Balance		36,753		1,882,970	4,527,055
Average Balance		$ 2,599,861		$ 4,659,453	$ 7,147,356
Rate		0.38%		0.88%	2.45%
Federal Home Loan Bank advances [Member]
Other Borrowed Funds [Line Items]
Balance		$ 0		$ 200,000	$ 4,500,000
Rate		0.00%		0.29%	1.79%
Average Balance		$ 1,679,315		$ 3,393,989	$ 7,122,466
Rate		0.27%		1.00%	2.44%
Maximum Outstanding At Any Month End		$ 2,600,000		$ 7,500,000	$ 8,000,000
GNMA repurchase liability [Member]
Other Borrowed Funds [Line Items]
Balance		$ 7,420		$ 19,500	$ 15,417
Rate		4.36%		4.35%	4.32%
Average Balance		$ 11,956		$ 42,771	$ 13,746
Rate		4.06%		4.18%	4.47%
Maximum Outstanding At Any Month End		$ 23,856		$ 126,569	$ 19,581
Federal Reserve Bank Advances
Other Borrowed Funds [Line Items]
Balance				$ 0
Rate				0.00%
Average Balance				$ 42,464
Rate				0.26%
Maximum Outstanding At Any Month End				$ 0
Paycheck protection program liquidity facility
Other Borrowed Funds [Line Items]
Balance		$ 0		$ 1,635,963
Rate		0.00%		0.35%
Average Balance		$ 879,145		$ 1,152,073
Rate		0.35%		0.35%
Maximum Outstanding At Any Month End		$ 1,662,598		$ 2,013,414
Other [Member]
Other Borrowed Funds [Line Items]
Balance		$ 29,333		$ 27,507	$ 11,638
Rate		3.23%		5.24%	5.09%
Average Balance		$ 29,445		$ 28,156	$ 11,144
Rate		4.18%		5.12%	5.30%
Maximum Outstanding At Any Month End		$ 31,875		$ 49,376	$ 34,676
Subordinated debentures [Member]
Other Borrowed Funds [Line Items]
Balance	[1]	$ 131,226		$ 276,005	$ 275,923
Rate	[1]	3.95%		4.72%	5.15%
Average Balance	[1]	$ 224,058		$ 275,965	$ 276,075
Rate	[1]	4.70%		5.05%	5.47%
Maximum Outstanding At Any Month End	[1]	$ 276,049		$ 276,005	$ 275,923
Subordinated debentures [Member] | Subordinated debentures, 2016 issuance [Member]
Other borrowed funds, Other Disclosures [Abstract]
Amount of debt issuance		$ 150,000
Maturity date		Jun. 30, 2056
Stated interest rate		5.375%
Gain (Loss) on Extinguishment of Debt		$ 5,200
Subordinated debentures [Member] | Subordinated debentures-acquired, 2015 Issuance [Member]
Other borrowed funds, Other Disclosures [Abstract]
Amount of debt issuance		$ 60,000
Maturity date		Jun. 25, 2030
Interest rate description		three-month LIBOR plus 3.17%
Stated interest rate		5.625%
Debt Instrument, Call Date, Earliest		Jun. 25, 2025
Subordinated debentures [Member] | Junior subordinated debentures-acquired, 2003 issuance [Member]
Other borrowed funds, Other Disclosures [Abstract]
Amount of debt issuance		$ 21,000
Maturity date		Sep. 17, 2033
Interest rate description		three-month LIBOR plus 2.95%
Subordinated debentures [Member] | Junior subordinated debentures-acquired, 2004 issuance [Member]
Other borrowed funds, Other Disclosures [Abstract]
Amount of debt issuance		$ 31,000
Maturity date		Jul. 23, 2034
Interest rate description		three-month LIBOR plus 2.60%
Subordinated debentures [Member] | Junior subordinated debentures-acquired, 2005 issuance [Member]
Other borrowed funds, Other Disclosures [Abstract]
Amount of debt issuance		$ 20,000
Maturity date		Sep. 30, 2035
Interest rate description		three-month LIBOR plus 1.45%
U.S. government agency mortgage-backed securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 907,154		893,069
Fair Value		2,144,507		910,885
Repurchase Liability	[2]	$ 2,126,936		$ 893,021
Average Rate (in hundredths)		1.58%		0.09%
U.S. government agency mortgage-backed securities [Member] | Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 907,154		$ 893,069
Fair Value		902,507		910,885
Repurchase Liability	[2]	$ 884,936		$ 893,021
Average Rate (in hundredths)		0.08%		0.09%
U.S. government agency mortgage-backed securities [Member] | Less than 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost				$ 0
Fair Value		$ 1,242,000	[3]	0
Repurchase Liability	[2]	$ 1,242,000	[3]	$ 0
Average Rate (in hundredths)		1.50%	[3]	0.00%
Subsidiaries [Member] | Funds purchased [Member]
Other borrowed funds, Other Disclosures [Abstract]
Number of days to maturity, minimum		1 day
Number of days to maturity, maximum		90 days
Subsidiaries [Member] | Repurchase agreements [Member]
Other borrowed funds, Other Disclosures [Abstract]
Number of days to maturity, maximum		90 days
Subsidiaries [Member] | Federal Home Loan Bank advances [Member]
Other borrowed funds, Other Disclosures [Abstract]
Federal Home Loan Banks, Letters of credit issued to secure public funds		$ 500,000
Unused credit available pursuant to the FHLB's collateral policies		5,900,000
Subsidiaries [Member] | BOK Financial Securities, Inc. [Member] | Other [Member]
Other Borrowed Funds [Line Items]
Balance		$ 0		$ 0

[1] Parent Company only.

[2] BOK Financial maintains control over the securities underlying overnight repurchase agreements and generally transfers control over securities underlying longer-term dealer repurchase agreements to the respective counterparty.

[3] Trading position.