Royalties And Licenses (Schedule Of Royalty-Related Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Mar. 31, 2020
Royalties and Licenses
Royalty-related assets	$ 46	$ 99
Other Current Assets
Royalties and Licenses
Royalty-related assets	25	74
Other assets
Royalties and Licenses
Royalty-related assets	$ 21	$ 25