Document And Entity Information - USD ($)	3 Months Ended
	Mar. 31, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	BOK FINANCIAL CORP ET AL
Entity Central Index Key	0000875357
Current Fiscal Year End Date	--12-31
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float		$ 2,441,480,672
Entity Common Stock, Shares Outstanding	71,449,982
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019