Business Segments - Segment Revenues (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 5,006	$ 4,912
Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	4,862	4,734
Other unallocated corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	144	178
North American Full-Service | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	3,299	3,240
North American Limited-Service | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	761	741
Asia Pacific | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	275	241
Other International | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 527	$ 512