Accounts Receivable (Allowance for Doubtful Accounts Activity) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Period	$ 3	$ 3	$ 4
Additions Charged to Expense	3	0	0
Accounts Recovered/ (Written- Off)	0	0	0
Foreign Exchange and Other	0	0	(1)
Balance at End of Period	$ 6	$ 3	$ 3