(Schedule Of Royalty-Related Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Mar. 31, 2020
Royalties And Licenses [Line Items]
Royalty-related assets	$ 44	$ 99
Other Current Assets [Member]
Royalties And Licenses [Line Items]
Royalty-related assets	24	74
Other Assets [Member]
Royalties And Licenses [Line Items]
Royalty-related assets	$ 20	$ 25