Commitments and Contingencies (Details) (USD $)			3 Months Ended
	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2013 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member]	Dec. 31, 2013 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2028 [Member]	Dec. 31, 2013 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2029 [Member]	Dec. 31, 2013 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2030 [Member]	Dec. 31, 2013 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2031 [Member]	Dec. 31, 2013 Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] 2032 [Member]
Commitment:
Credit facilities commitments with vehicle and industrial equipment dealers	$ 1,137,000,000	$ 1,106,000,000
Minimum lease commitments	66,000,000	74,000,000
Total commitments	1,203,000,000	1,180,000,000
Guarantor Obligations [Line Items]
Guarantees of affiliate pollution control and solid waste disposal bonds	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	1,303,000,000	1,280,000,000
Future minimum lease payments under non-cancelable operating leases
2014	5,000,000
2015	19,000,000
2016	18,000,000
2017	13,000,000
2018	8,000,000
Thereafter	3,000,000
Total	66,000,000	74,000,000
Facility lease commitments with affiliate	$ 32,000,000	$ 37,000,000