Income Taxes 3 (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Schedule of effective income tax rate reconciliation
Tax expense at U.S. federal statutory tax rate	$ 376	$ 379	$ 390
Effect of international operations	(70)	(77)	(91)
U.S. federal and state tax contingencies	0	8	1
Domestic manufacturing deduction	(23)	(27)	(23)
State taxes, net of U.S. federal tax benefit	16	16	15
Valuation allowance	(16)	3	8
Other, net	15	13	5
Income tax expense from continuing operations	$ 298	$ 315	$ 305