XML 11 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document And Entity Information - USD ($)
 9 Months Ended
Sep. 30, 2018
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 65,434,258  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2018