Commitments and Contingencies (Details) (USD $)			3 Months Ended
	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2012 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member]	Sep. 30, 2012 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2028 [Member]	Sep. 30, 2012 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2029 [Member]	Sep. 30, 2012 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2030 [Member]	Sep. 30, 2012 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2031 [Member]	Sep. 30, 2012 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2032 [Member]
Commitment:
Credit facilities with vehicle and industrial equipment dealers	$ 6,944,000,000	$ 6,804,000,000
Minimum lease commitments	81,000,000	81,000,000
Total commitments	7,025,000,000	6,885,000,000
Guarantor Obligations [Line Items]
Guaranteed Bond Obligations	100,000,000	100,000,000	100,000,000	20,000,000	50,000,000	10,000,000	10,000,000	10,000,000
Guaranty Fee			78,000
Total commitments and guarantees	7,125,000,000	6,985,000,000
Wholesale financing demand note facilities	10,875,000,000	10,258,000,000
Future minimum lease payments under non-cancelable operating leases
2013	10,000,000
2014	19,000,000
2015	16,000,000
2016	15,000,000
2017	11,000,000
Thereafter	10,000,000
Total	81,000,000	81,000,000
Facility lease commitments with affiliate	41,000,000	44,000,000
Wholesale financing demand note facilities amounts outstanding	7,500,000,000	6,600,000,000
Credit facilities with vehicle and industrial equipment dealers amount outstanding	$ 6,000,000,000	$ 5,800,000,000