Investment in and Advances to Non-Consolidated Affiliates and Related Party Transactions (Results of Operations of Equity Method Affiliates) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Summary of the share of the condensed results of operations of equity method affiliates
Net sales	$ 447	$ 464	$ 524
Costs and expenses related to net sales	463	463	527
Provision for taxes on income	(5)	2	0
Net loss	(11)	(1)	(3)
Purchase of tolling services from Alunorf	$ 224	$ 232	$ 261