Property and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,881	$ 2,378
Accumulated depreciation	(896)	(918)
Property and equipment, net	985	1,460
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	299	457
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	692	781
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	777	775
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 113	$ 365