Other Assets and Other Liabilities - Other Assets and Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Mar. 31, 2015
Other assets:
Notes receivable from affiliates	$ 1,126	$ 1,184
Used vehicles held for sale	313	188
Deferred charges	116	122
Income taxes receivable	0	174
Derivative assets	53	53
Other assets	695	561
Total other assets	2,303	2,282
Other liabilities:
Unearned insurance premiums and contract revenues	1,957	1,825
Derivative liabilities	75	90
Accounts payable and accrued expenses	1,027	855
Deferred income	453	405
Income taxes payable	76	0
Other liabilities	134	180
Total other liabilities	$ 3,722	$ 3,355