Interest And Other Income (Expense), Net (Schedule Of Interest And Other Income (Expense), Net) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Interest and Other Income [Abstract]
Loss on Conversion of Convertible Notes	$ 0	$ (10)	$ 0
Interest expense	(47)	(28)	(31)
Interest income	25	15	10
Net gain (loss) on foreign currency transactions	(40)	(14)	(62)
Net gain (loss) on foreign currency forward contracts	46	15	59
Other income, net	2	1	1
Interest and other income (expense), net	$ (14)	$ (21)	$ (23)