Income Taxes 3 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Schedule of effective income tax rate reconciliation
Tax expense at U.S. federal statutory tax rate	$ 390	$ 356	$ 440
Effect of international operations	(91)	(147)	(131)
U.S. federal and state tax contingencies	1	(123)	(8)
Domestic manufacturing deduction	(23)	(24)	(21)
State taxes, net of U.S. federal tax benefit	15	19	23
Valuation allowance	8	23	11
Other, net	5	25	25
Income tax expense from continuing operations	$ 305	$ 129	$ 339