Interest And Other Income (Expense), Net (Schedule Of Interest And Other Income (Expense), Net) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Interest and Other Income [Abstract]
Interest expense	$ (45)	$ (44)	$ (47)
Interest income	88	50	25
Net gain (loss) on foreign currency transactions	(9)	18	(40)
Net gain (loss) on foreign currency forward contracts	50	(16)	46
Other income, net	(1)	7	2
Interest and other income (expense), net	$ 83	$ 15	$ (14)