v3.10.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2018
Oct. 31, 2018
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Entity Emerging Growth Company false  
Entity Small Business false  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Trading Symbol ZG  
Entity Registrant Name ZILLOW GROUP, INC.  
Entity Central Index Key 0001617640  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Class A Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   57,986,928
Class B Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   6,217,447
Class C Capital Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   139,042,266