Other Assets and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012
Other assets:
Notes receivable from alliliates	$ 1,288	$ 931
Used vehicle held for sale	233	265
Deferred charges	109	120
Income taxes receivable	7	13
Derivative assets	62	58
Other assets	435	353
Total other assets	2,134	1,740
Other liabilities:
Unearned insurance premiums and contract revenues	1,611	1,528
Derivative liabilities	10	17
Accounts payable and accrued expenses	790	685
Deferred income	302	255
Other liabilities	166	192
Total other liabilities	2,879	2,677
Non cash activities for used vehicles held for sale	$ 32		$ 37