Other Assets and Other Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011
Other assets:
Notes receivable from alliliates	$ 612	$ 1,052
Used vehicle held for sale	88	82
Deferred charges	125	131
Income taxes receivable	25	23
Derivative assets	199	70
Other assets	412	369
Total other assets	1,461	1,727
Other liabilities:
Unearned insurance premiums and contract revenues	1,475	1,467
Derivative liabilities	50	67
Accounts payable and accrued expenses	750	716
Deferred income	233	229
Other liabilities	104	126
Total other liabilities	2,612	2,605
Non cash activities for used vehicles held for sale	$ 6		$ 52