Vehicle Leasing Activities (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Operating Leases:
Vehicles under operating leases	$ 8,309	$ 8,328
Less: Accumulated depreciation	(4,932)	(4,959)
Net investment in operating leases	3,377	3,369
Direct Financing Leases:
Lease payments receivable	96	91
Less: Unearned income	(2)
Net investment in direct financing leases	94	91
Off-Lease Vehicles:
Vehicles not yet subject to a lease	225	169
Vehicles held for sale	11	15
Less: Accumulated depreciation	(6)	(8)
Net investment in off-lease vehicles	230	176
Net investment in fleet leases	3,701	3,636
Vehicles under open-end operating leases
Operating Leases:
Vehicles under operating leases	8,167	8,174
Vehicles under closed-end operating leases
Operating Leases:
Vehicles under operating leases	$ 142	$ 154