v3.10.0.1
Document and Entity Information - USD ($)
$ in Billions
12 Months Ended
Dec. 31, 2018
Jan. 31, 2019
Jun. 29, 2018
Entity Registrant Name Liberty TripAdvisor Holdings, Inc.    
Entity Central Index Key 0001606745    
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Public Float     $ 1.1
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Series A      
Entity Common Stock, Shares Outstanding   72,146,903  
Series B      
Entity Common Stock, Shares Outstanding   2,929,777