Leased Vehicles Minimum rental payments (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014
Operating Leases, Future Minimum Payments Receivable [Abstract]
Operating Leases, Future Minimum Payments Receivable, Current	$ 272
Operating Leases, Future Minimum Payments Receivable, in Two Years	1,012
Operating Leases, Future Minimum Payments Receivable, in Three Years	780
Operating Leases, Future Minimum Payments Receivable, in Four Years	366
Operating Leases, Future Minimum Payments Receivable, in Five Years	51
Operating Leases, Future Minimum Payments Receivable, Thereafter	$ 3