Other Assets and Other Liabilities - Other Assets and Other Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Mar. 31, 2015
Other assets:
Notes receivable from affiliates	$ 707	$ 1,184
Used vehicles held for sale	174	188
Deferred charges	116	122
Income taxes receivable	10	174
Derivative assets	47	53
Other assets	601	561
Total other assets	1,655	2,282
Other liabilities:
Unearned insurance premiums and contract revenues	1,871	1,825
Derivative liabilities	43	90
Accounts payable and accrued expenses	937	855
Deferred income	430	405
Other liabilities	165	180
Total other liabilities	$ 3,446	$ 3,355