Variable Interest Entities - Schedule of Assets and Liabilities related to Variable Interest Entities Securitization Transactions (Details) - USD ($) $ in Millions	Jun. 30, 2017	Mar. 31, 2017
Variable Interest Entity [Line Items]
Restricted Cash	$ 1,011	$ 1,087
Net Securitized Assets	68,771	68,462
Other Assets	2,187	2,044
Debt	98,776	98,233
Other liabilities	3,955	3,952
Variable Interest Entities Assets [Member]
Variable Interest Entity [Line Items]
Restricted Cash	991	1,067
Gross Securitized Assets	19,366	19,573
Net Securitized Assets	17,450	17,753
Other Assets	100	87
Variable Interest Entities Liabilities [Member]
Variable Interest Entity [Line Items]
Debt	13,813	14,319
Other liabilities	6	6
Retail Finance Receivables [Member] | Variable Interest Entities Assets [Member]
Variable Interest Entity [Line Items]
Restricted Cash	748	856
Gross Securitized Assets	12,692	13,071
Net Securitized Assets	12,494	12,865
Other Assets	5	7
Retail Finance Receivables [Member] | Variable Interest Entities Liabilities [Member]
Variable Interest Entity [Line Items]
Debt	10,546	11,017
Other liabilities	5	5
Investments In Operating Leases, Net [Member] | Variable Interest Entities Assets [Member]
Variable Interest Entity [Line Items]
Restricted Cash	243	211
Gross Securitized Assets	6,674	6,502
Net Securitized Assets	4,956	4,888
Other Assets	95	80
Investments In Operating Leases, Net [Member] | Variable Interest Entities Liabilities [Member]
Variable Interest Entity [Line Items]
Debt	3,267	3,302
Other liabilities	$ 1	$ 1