Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Net interest revenue from external sources	$ 274,018	$ 280,309	$ 542,429	$ 560,729
Net interest revenue (expense) from internal sources	0	0	0	0
Net interest revenue	274,018	280,309	542,429	560,729
Provision for credit losses	0	(35,000)	0	(60,000)
Net interest revenue after provision for credit losses	274,018	315,309	542,429	620,729
Other operating revenue	168,617	191,446	256,473	368,500
Other operating expense	273,655	291,152	551,273	586,936
Net direct contribution	168,980	215,603	247,629	402,293
Gain (loss) on financial instruments, net	0	0	0	0
Change in fair value of mortgage servicing rights	0	0	0	0
Gain (loss) on repossessed assets, net	0	0	0	0
Corporate expense allocations	0	0	0	0
Net income before taxes	168,980	215,603	247,629	402,293
Federal and state income taxes	36,122	48,496	52,319	90,878
Net income	132,858	167,107	195,310	311,415
Net income (loss) attributable to non-controlling interests	12	686	(24)	(1,066)
Net income attributable to BOK Financial Corp. shareholders	132,846	166,421	195,334	312,481
Average assets	47,288,534	50,196,922	48,915,764	50,253,463
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	172,974	151,942	320,564	307,741
Net interest revenue (expense) from internal sources	(6,452)	(21,041)	(17,031)	(46,835)
Net interest revenue	166,522	130,901	303,533	260,906
Provision for credit losses	(1,502)	16,268	3,841	30,253
Net interest revenue after provision for credit losses	168,024	114,633	299,692	230,653
Other operating revenue	61,688	65,269	119,115	111,848
Other operating expense	70,009	71,351	135,123	138,330
Net direct contribution	159,703	108,551	283,684	204,171
Gain (loss) on financial instruments, net	61	34	(143)	67
Change in fair value of mortgage servicing rights	0	0	0	0
Gain (loss) on repossessed assets, net	(4,515)	3,565	(2,722)	16,302
Corporate expense allocations	16,634	12,512	32,880	25,246
Net income before taxes	138,615	99,638	247,939	195,294
Federal and state income taxes	33,818	27,006	60,798	52,989
Net income	104,797	72,632	187,141	142,305
Net income (loss) attributable to non-controlling interests	0	0	0	0
Net income attributable to BOK Financial Corp. shareholders	104,797	72,632	187,141	142,305
Average assets	29,269,712	28,160,594	29,545,278	28,104,137
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	16,784	17,552	33,699	34,238
Net interest revenue (expense) from internal sources	17,002	7,393	27,294	11,681
Net interest revenue	33,786	24,945	60,993	45,919
Provision for credit losses	1,196	425	2,308	1,561
Net interest revenue after provision for credit losses	32,590	24,520	58,685	44,358
Other operating revenue	30,089	37,714	64,050	89,996
Other operating expense	52,660	52,453	101,449	108,076
Net direct contribution	10,019	9,781	21,286	26,278
Gain (loss) on financial instruments, net	(15,860)	17,137	(73,755)	(12,479)
Change in fair value of mortgage servicing rights	17,485	(13,041)	66,595	20,833
Gain (loss) on repossessed assets, net	93	0	138	41
Corporate expense allocations	10,120	11,599	22,200	23,073
Net income before taxes	1,617	2,278	(7,936)	11,600
Federal and state income taxes	378	580	(1,858)	2,954
Net income	1,239	1,698	(6,078)	8,646
Net income (loss) attributable to non-controlling interests	0	0	0	0
Net income attributable to BOK Financial Corp. shareholders	1,239	1,698	(6,078)	8,646
Average assets	10,338,191	10,087,488	10,306,218	9,922,431
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	39,412	52,966	95,643	101,520
Net interest revenue (expense) from internal sources	(1,665)	(673)	(2,130)	(873)
Net interest revenue	37,747	52,293	93,513	100,647
Provision for credit losses	(60)	(54)	(131)	(83)
Net interest revenue after provision for credit losses	37,807	52,347	93,644	100,730
Other operating revenue	86,761	79,149	111,779	145,272
Other operating expense	76,393	79,518	151,012	158,187
Net direct contribution	48,175	51,978	54,411	87,815
Gain (loss) on financial instruments, net	0	0	0	0
Change in fair value of mortgage servicing rights	0	0	0	0
Gain (loss) on repossessed assets, net	0	0	0	0
Corporate expense allocations	12,503	10,352	24,575	20,249
Net income before taxes	35,672	41,626	29,836	67,566
Federal and state income taxes	8,385	10,638	7,070	17,281
Net income	27,287	30,988	22,766	50,285
Net income (loss) attributable to non-controlling interests	0	0	0	0
Net income attributable to BOK Financial Corp. shareholders	27,287	30,988	22,766	50,285
Average assets	16,902,721	19,201,041	19,101,045	18,924,987
Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	44,848	57,849	92,523	117,230
Net interest revenue (expense) from internal sources	(8,885)	14,321	(8,133)	36,027
Net interest revenue	35,963	72,170	84,390	153,257
Provision for credit losses	366	(51,639)	(6,018)	(91,731)
Net interest revenue after provision for credit losses	35,597	123,809	90,408	244,988
Other operating revenue	(9,921)	9,314	(38,471)	21,384
Other operating expense	74,593	87,830	163,689	182,343
Net direct contribution	(48,917)	45,293	(111,752)	84,029
Gain (loss) on financial instruments, net	15,799	(17,171)	73,898	12,412
Change in fair value of mortgage servicing rights	(17,485)	13,041	(66,595)	(20,833)
Gain (loss) on repossessed assets, net	4,422	(3,565)	2,584	(16,343)
Corporate expense allocations	(39,257)	(34,463)	(79,655)	(68,568)
Net income before taxes	(6,924)	72,061	(22,210)	127,833
Federal and state income taxes	(6,459)	10,272	(13,691)	17,654
Net income	(465)	61,789	(8,519)	110,179
Net income (loss) attributable to non-controlling interests	12	686	(24)	(1,066)
Net income attributable to BOK Financial Corp. shareholders	(477)	61,103	(8,495)	111,245
Average assets	$ (9,222,090)	$ (7,252,201)	$ (10,036,777)	$ (6,698,092)