Commitments and Contingencies (Details) (USD $)	3 Months Ended
	Jun. 30, 2013	Mar. 31, 2013
Commitment:
Credit facilities with vehicle and industrial equipment dealers	$ 7,552,000,000	$ 7,396,000,000
Less: Funded commitments	6,352,000,000	6,290,000,000
Unfunded commitments	1,200,000,000	1,106,000,000
Minimum lease commitments	70,000,000	74,000,000
Total unfunded commitments	1,270,000,000	1,180,000,000
Guarantor Obligations [Line Items]
Total commitments and guarantees	1,370,000,000	1,280,000,000
Wholesale financing demand note facilities	11,753,000,000	11,475,000,000
Less: Funded facilites	8,951,000,000	8,284,000,000
Unfunded wholesale financing demand note facilities	2,802,000,000	3,191,000,000
Future minimum lease payments under non-cancelable operating leases
2014	14,000,000
2015	18,000,000
2016	17,000,000
2017	12,000,000
2018	7,000,000
Thereafter	2,000,000
Total	70,000,000	74,000,000
Facility lease commitments with affiliate	35,000,000	37,000,000
Affiliate Pollution Control and Solid Waste Disposal Bonds [Member]
Guarantor Obligations [Line Items]
Guaranteed Bond Obligations	100,000,000	100,000,000
Guaranty Fee	78,000
Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] | 2028 [Member]
Guarantor Obligations [Line Items]
Guaranteed Bond Obligations	20,000,000
Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] | 2029 [Member]
Guarantor Obligations [Line Items]
Guaranteed Bond Obligations	50,000,000
Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] | 2030 [Member]
Guarantor Obligations [Line Items]
Guaranteed Bond Obligations	10,000,000
Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] | 2031 [Member]
Guarantor Obligations [Line Items]
Guaranteed Bond Obligations	10,000,000
Affiliate Pollution Control and Solid Waste Disposal Bonds [Member] | 2032 [Member]
Guarantor Obligations [Line Items]
Guaranteed Bond Obligations	$ 10,000,000