Properties and Equipment, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 762	$ 744
Accumulated depreciation and amortization	(577)	(542)
Properties and equipment, net	185	202
Depreciation and amortization	51	60	$ 59
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	8	8
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	609	594
Furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 145	$ 142