Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Variable Interest Entity [Line Items]
Securities retained by TMCC	$ 466	$ 381
Amounts due from dealers	14	15
Revenue earned from dealers	1	1	1
Variable Interest Entities Securitized Assets [Member]
Variable Interest Entity [Line Items]
Restricted Cash	491	682
Gross Securitized Assets	8,299	10,726
Net Securitized Assets	7,990	10,527
Other assets	12	3
Variable Interest Entities Securitized Assets [Member] | Retail Finance Receivables [Member]
Variable Interest Entity [Line Items]
Restricted Cash	458	682
Gross Securitized Assets	7,669	10,726
Net Securitized Assets	7,556	10,527
Other assets	3	3
Variable Interest Entities Securitized Assets [Member] | Investments In Operating Leases, Net [Member]
Variable Interest Entity [Line Items]
Restricted Cash	33	0
Gross Securitized Assets	630	0
Net Securitized Assets	434	0
Other assets	9	0
Related Liabilities [Member]
Variable Interest Entity [Line Items]
Debt	7,009	9,789
Other Liabilities	1	2
Related Liabilities [Member] | Retail Finance Receivables [Member]
Variable Interest Entity [Line Items]
Debt	6,738	9,789
Other Liabilities	1	2
Related Liabilities [Member] | Investments In Operating Leases, Net [Member]
Variable Interest Entity [Line Items]
Debt	271	0
Other Liabilities	$ 0	$ 0