Quarterly report pursuant to Section 13 or 15(d)

Intangible Assets (Amortization Expense of Amortizable Intangible Assets) (Details)

v3.10.0.1
Intangible Assets (Amortization Expense of Amortizable Intangible Assets) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Finite-Lived Intangible Assets [Line Items]        
Amortization expense $ 7 $ 5 $ 12 $ 10
Other        
Finite-Lived Intangible Assets [Line Items]        
Amortization expense 1 0 1 1
Franchise agreements        
Finite-Lived Intangible Assets [Line Items]        
Amortization expense 5 4 9 8
Management agreements        
Finite-Lived Intangible Assets [Line Items]        
Amortization expense $ 1 $ 1 $ 2 $ 1