Royalties And Licenses (Schedule Of Royalty-Related Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Mar. 31, 2017
Royalties and Licenses
Royalty-related assets	$ 54	$ 118
Other Current Assets
Royalties and Licenses
Royalty-related assets	20	79
Other assets
Royalties and Licenses
Royalty-related assets	$ 34	$ 39