Income Taxes 3 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Tax expense from continuing operations is reconciled to the tax expense
Tax expense at U.S. federal statutory tax	$ 474	$ 423	$ 403
Effect of international operations	(89)	(129)	(55)
US federal and state tax contingencies	23	61	14
State taxes, net of federal tax benefit	17	13	7
Valuation Allowance	(15)	(2)	5
Other, net	6	20	19
Income tax expense	$ 416	$ 386	$ 393