v3.10.0.1
Document And Entity Information - shares
9 Months Ended
Sep. 30, 2018
Oct. 31, 2018
Entity Information [Line Items]    
Entity Registrant Name Discovery, Inc.  
Entity Central Index Key 0001437107  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Series A Common Stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   156,742,885
Series B Common Stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   6,512,378
Series C Common Stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   360,244,964