Business Segments - Segment Revenues (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 3,902	$ 3,689	$ 7,674	$ 7,202
Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	3,837	3,622	7,547	7,077
Other unallocated corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	65	67	127	125
North American Full-Service Segment | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	2,360	2,252	4,681	4,427
North American Limited-Service Segment | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	906	821	1,739	1,559
International | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 571	$ 549	$ 1,127	$ 1,091