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Segment and Geographic Information - Summary of Segment Information (Parenthetical) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Segment Reporting Information [Line Items]      
General and administrative [1] $ 173 $ 187 $ 177
Advertising expense 118 423 544
Reportable Segments | Hotels, Media & Platform      
Segment Reporting Information [Line Items]      
General and administrative 70 69 77
Advertising expense $ 10 $ 77 $ 122
[1] Includes stock-based compensation expense as follows (Note 15):