Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Net interest revenue from external sources	$ 268,411	$ 280,420
Net interest revenue (expense) from internal sources	0	0
Net interest revenue	268,411	280,420
Provision for credit losses	0	(25,000)
Net interest revenue after provision for credit losses	268,411	305,420
Other operating revenue	87,856	177,054
Other operating expense	277,618	295,784
Net direct contribution	78,649	186,690
Gain (loss) on financial instruments, net	0	0
Change in fair value of mortgage servicing rights	0	0
Gain (loss) on repossessed assets, net	0	0
Corporate expense allocations	0	0
Net income before taxes	78,649	186,690
Federal and state income taxes	16,197	42,382
Net income	62,452	144,308
Net income (loss) attributable to non-controlling interests	(36)	(1,752)
Net income attributable to BOK Financial Corp. shareholders	62,488	146,060
Average assets	50,561,074	50,310,633
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	147,590	155,799
Net interest revenue (expense) from internal sources	(10,579)	(25,794)
Net interest revenue	137,011	130,005
Provision for credit losses	5,343	13,985
Net interest revenue after provision for credit losses	131,668	116,020
Other operating revenue	57,427	46,579
Other operating expense	65,114	66,979
Net direct contribution	123,981	95,620
Gain (loss) on financial instruments, net	(204)	33
Change in fair value of mortgage servicing rights	0	0
Gain (loss) on repossessed assets, net	1,793	12,737
Corporate expense allocations	16,246	12,734
Net income before taxes	109,324	95,656
Federal and state income taxes	26,980	25,983
Net income	82,344	69,673
Net income (loss) attributable to non-controlling interests	0	0
Net income attributable to BOK Financial Corp. shareholders	82,344	69,673
Average assets	29,823,905	28,047,052
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	16,915	16,686
Net interest revenue (expense) from internal sources	10,292	4,288
Net interest revenue	27,207	20,974
Provision for credit losses	1,112	1,136
Net interest revenue after provision for credit losses	26,095	19,838
Other operating revenue	33,961	52,282
Other operating expense	48,789	55,622
Net direct contribution	11,267	16,498
Gain (loss) on financial instruments, net	(57,895)	(29,616)
Change in fair value of mortgage servicing rights	49,110	33,874
Gain (loss) on repossessed assets, net	45	41
Corporate expense allocations	12,080	11,475
Net income before taxes	(9,553)	9,322
Federal and state income taxes	(2,236)	2,374
Net income	(7,317)	6,948
Net income (loss) attributable to non-controlling interests	0	0
Net income attributable to BOK Financial Corp. shareholders	(7,317)	6,948
Average assets	10,273,890	9,755,539
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	56,231	48,554
Net interest revenue (expense) from internal sources	(465)	(200)
Net interest revenue	55,766	48,354
Provision for credit losses	(71)	(29)
Net interest revenue after provision for credit losses	55,837	48,383
Other operating revenue	25,018	66,123
Other operating expense	74,495	78,565
Net direct contribution	6,360	35,941
Gain (loss) on financial instruments, net	0	0
Change in fair value of mortgage servicing rights	0	0
Gain (loss) on repossessed assets, net	0	0
Corporate expense allocations	12,062	9,887
Net income before taxes	(5,702)	26,054
Federal and state income taxes	(1,283)	6,672
Net income	(4,419)	19,382
Net income (loss) attributable to non-controlling interests	0	0
Net income attributable to BOK Financial Corp. shareholders	(4,419)	19,382
Average assets	21,323,795	18,645,865
Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	47,675	59,381
Net interest revenue (expense) from internal sources	752	21,706
Net interest revenue	48,427	81,087
Provision for credit losses	(6,384)	(40,092)
Net interest revenue after provision for credit losses	54,811	121,179
Other operating revenue	(28,550)	12,070
Other operating expense	89,220	94,618
Net direct contribution	(62,959)	38,631
Gain (loss) on financial instruments, net	58,099	29,583
Change in fair value of mortgage servicing rights	(49,110)	(33,874)
Gain (loss) on repossessed assets, net	(1,838)	(12,778)
Corporate expense allocations	(40,388)	(34,096)
Net income before taxes	(15,420)	55,658
Federal and state income taxes	(7,264)	7,353
Net income	(8,156)	48,305
Net income (loss) attributable to non-controlling interests	(36)	(1,752)
Net income attributable to BOK Financial Corp. shareholders	(8,120)	50,057
Average assets	$ (10,860,516)	$ (6,137,823)