Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Impact of Adoption of ASC 606 (Details)

v3.10.0.1
Summary of Significant Accounting Policies - Impact of Adoption of ASC 606 (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Jan. 01, 2018
Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Retained earnings $ 133   $ 196
Noncontrolling interests in equity of subsidiaries $ 3,400   $ 3,329
Customer invoices due 30 days    
Impact of Accounting ASC 606 | ASU 2014-09      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Retained earnings   $ 1  
Noncontrolling interests in equity of subsidiaries   3  
TripAdvisor      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Capitalized contract costs $ 2    
Customer invoices due 30 days    
Maximum subscription advertising service contact period 1 year    
Practical expedient, incremental costs true    
Practical expedient, remaining performance obligation true    
TripAdvisor | Impact of Accounting ASC 606 | ASU 2014-09      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Retained earnings   $ 4