Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Mar. 31, 2014
Variable Interest Entity [Line Items]
Securities retained by TMCC	$ 991	$ 1,169
Variable Interest Entities Securitized Assets [Member]
Variable Interest Entity [Line Items]
Restricted Cash	621	644
Gross Securitized Assets	11,465	9,881
Net Securitized Assets	10,945	9,657
Other assets	12	7
Variable Interest Entities Securitized Assets [Member] | Retail Finance Receivables [Member]
Variable Interest Entity [Line Items]
Restricted Cash	574	624
Gross Securitized Assets	9,757	9,633
Net Securitized Assets	9,616	9,501
Other assets	3	3
Variable Interest Entities Securitized Assets [Member] | Investments In Operating Leases, Net [Member]
Variable Interest Entity [Line Items]
Restricted Cash	47	20
Gross Securitized Assets	1,708	248
Net Securitized Assets	1,329	156
Other assets	9	4
Related Liabilities [Member]
Variable Interest Entity [Line Items]
Debt	9,335	8,158
Other Liabilities	2	2
Related Liabilities [Member] | Retail Finance Receivables [Member]
Variable Interest Entity [Line Items]
Debt	8,362	8,146
Other Liabilities	2	2
Related Liabilities [Member] | Investments In Operating Leases, Net [Member]
Variable Interest Entity [Line Items]
Debt	973	12
Other Liabilities	$ 0	$ 0