Document And Entity Information - shares
6 Months Ended
Dec. 31, 2018
Jan. 31, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Dec. 31, 2018  
Entity Registrant Name CDK Global, Inc.  
Entity Central Index Key 0001609702  
Current Fiscal Year End Date --06-30  
Entity Filer Category Large Accelerated Filer  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   124,712,345