Other Assets and Other Liabilities - Other Assets and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other assets:
Notes receivable from affiliates	$ 1,184	$ 1,172
Used vehicles held for sale	188	139
Deferred charges	122	116
Income taxes receivable	174	0
Derivative assets	53	49
Other assets	561	394
Total other assets	2,282	1,870
Other liabilities:
Unearned insurance premiums and contract revenues	1,825	1,665
Derivative liabilities	90	6
Accounts payable and accrued expenses	855	746
Deferred income	405	332
Other liabilities	180	139
Total other liabilities	$ 3,355	$ 2,888