Interest And Other Income (Expense), Net (Schedule Of Interest And Other Income (Expense), Net) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Interest and Other Income [Abstract]
Interest expense	$ (44)	$ (45)	$ (44)
Interest income	100	88	50
Net gain (loss) on foreign currency transactions	11	(9)	18
Net gain (loss) on foreign currency forward contracts	(4)	50	(16)
Other income, net	0	(1)	7
Interest and other income (expense), net	$ 63	$ 83	$ 15