Business Segments - Segment Revenues (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 3,942	$ 3,578	$ 11,616	$ 10,780
Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	3,703	3,506	11,250	10,583
Other unallocated corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	239	72	366	197
North American Full-Service Segment | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	2,222	2,128	6,903	6,555
North American Limited-Service Segment | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	936	846	2,675	2,405
International | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 545	$ 532	$ 1,672	$ 1,623