Quarterly report pursuant to Section 13 or 15(d)

Transactions With Former Parent (Narrative) (Details)

v3.10.0.1
Transactions With Former Parent (Narrative) (Details) - Wyndham Worldwide - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Related Party Transaction [Line Items]      
Outstanding borrowings from Parent     $ 184
Indirect General Corporate Overhead [Member]      
Related Party Transaction [Line Items]      
Expense for services provided by Parent $ 12 $ 18  
Information technology support, financial services, human resources and other shared services      
Related Party Transaction [Line Items]      
Expense for services provided by Parent 13 14  
Insurance      
Related Party Transaction [Line Items]      
Expense for services provided by Parent 1 1  
Defined contribution benefit plan      
Related Party Transaction [Line Items]      
Expense for services provided by Parent $ 2 $ 3