Other Assets and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012
Other assets:
Notes receivable from alliliates	$ 1,250	$ 931
Used vehicle held for sale	185	265
Deferred charges	112	120
Income taxes receivable	12	13
Derivative assets	47	58
Other assets	373	353
Total other assets	1,979	1,740
Other liabilities:
Unearned insurance premiums and contract revenues	1,565	1,528
Derivative liabilities	65	17
Accounts payable and accrued expenses	773	685
Deferred income	275	255
Other liabilities	158	192
Total other liabilities	2,836	2,677
Non cash activities for used vehicles held for sale	$ 80		$ 6