Leased Vehicles - Summary of Leased Vehicles (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Property Subject to or Available for Operating Lease, Net [Abstract]
Leased vehicles	$ 17,410	$ 9,747
Manufacturer incentives	(2,745)	(1,479)
Leased vehicles accounted for operating leases net of manufacturing incentives	14,665	8,268
Less: accumulated depreciation	(1,761)	(1,208)
Leased vehicles, net	$ 12,904	$ 7,060