Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Stock-Based Compensation Expense) (Details)

v3.8.0.1
Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation $ 3 $ 2
Wyndham Worldwide    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation $ 3 $ 2