Vehicle Leasing Activities (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Operating Leases:
Vehicles under operating leases	$ 8,076	$ 8,111
Less: Accumulated depreciation	(4,790)	(4,777)
Net investment in operating leases	3,286	3,334
Direct Financing Leases:
Lease payments receivable	102	100
Less: Unearned income	(6)	(2)
Net investment in direct financing leases	96	98
Off-Lease Vehicles:
Vehicles not yet subject to a lease	233	217
Vehicles held for sale	11	10
Less: Accumulated depreciation	(7)	(6)
Net investment in off-lease vehicles	237	221
Net investment in fleet leases	3,619	3,653
Vehicles under open-end operating leases
Operating Leases:
Vehicles under operating leases	7,948	7,974
Vehicles under closed-end operating leases
Operating Leases:
Vehicles under operating leases	$ 128	$ 137