Royalties And Licenses (Schedule Of Royalty-Related Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Mar. 31, 2018
Royalties and Licenses
Royalty-related assets	$ 91	$ 102
Other Current Assets
Royalties and Licenses
Royalty-related assets	59	68
Other assets
Royalties and Licenses
Royalty-related assets	$ 32	$ 34