Income Taxes 5 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Roll-forward of uncertain tax positions
Balance at beginning of year	$ 523	$ 522
Additions for tax positions related to the current year	30	26
Additions for tax positions from prior years	60	21
Reductions for tax positions from prior years	(158)	(17)
Settlement payments	(55)	(19)
Statute of limitations expiration	(15)	(6)
Translation and other	(3)	(4)
Balance at end of year	$ 382	$ 523