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Business Segments - Segment Profits (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment profits	$ 607			$ 596			$ 1,526	$ 1,944
Interest expense, net of interest income	(92)			(81)			(279)	(230)
Income taxes	(140)			(91)			(279)	(410)
NET INCOME	387	$ 232	$ 375	503	$ 667	$ 420	994	1,590
Unallocated corporate
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment profits	(77)			(61)			(634)	(182)
North American Full-Service \| Total segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment profits	255			248			882	919
North American Limited-Service \| Total segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment profits	238			206			693	640
Asia Pacific \| Total segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment profits	81			106			276	358
Other International \| Total segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment profits	$ 122			$ 176			$ 335	$ 495