Property and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation	$ 69	$ 72	$ 139	$ 141
Net capital lease assets included in property and equipment	1		1		$ 20
Accumulated depreciation of capital lease assets included in property and equipment	0		0		10
Hurricanes Irma and Maria [Member]
Property, Plant and Equipment [Line Items]
Expenses on property and equipment from hurricane damage			37		20
Loss on property and equipment from hurricane damage			22		$ 54
Additional insurance receivable recognized for property and equipment damaged from hurricanes			59
Insurance proceeds received on hurricanes damage			43
Hurricanes Irma and Maria [Member] | Ancillary Hotel Revenue [Member]
Property, Plant and Equipment [Line Items]
Business interruption insurance recovery			7
Hurricanes Irma and Maria [Member] | Other Assets [Member]
Property, Plant and Equipment [Line Items]
Insurance settlements receivable on hurricanes damage	$ 80		$ 80