Interest And Other Income (Expense), Net (Schedule Of Interest And Other Income (Expense), Net) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Interest and Other Income [Abstract]
Interest expense	$ (45)	$ (44)	$ (45)
Interest income	24	100	88
Net gain (loss) on foreign currency transactions	9	11	(9)
Net gain (loss) on foreign currency forward contracts	(19)	(4)	50
Other income, net	2	0	(1)
Interest and other income (expense), net	$ (29)	$ 63	$ 83