(Schedule Of Royalty-Related Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Royalties And Licenses [Line Items]
Royalty-related assets	$ 83	$ 102
Other Current Assets [Member]
Royalties And Licenses [Line Items]
Royalty-related assets	53	68
Other Assets [Member]
Royalties And Licenses [Line Items]
Royalty-related assets	$ 30	$ 34