Property and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Property and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 871	$ 815
Less accumulated depreciation and amortization	(426)	(377)
Property, Plant and Equipment, Total	445	438
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	98	97
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	226	223
Non-rental vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	86	75
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	78	68
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	171	152
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 212	$ 200