(Schedule Of Royalty-Related Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Mar. 31, 2017
Royalties And Licenses [Line Items]
Royalty-related assets	$ 102	$ 118
Other Current Assets [Member]
Royalties And Licenses [Line Items]
Royalty-related assets	68	79
Other Assets [Member]
Royalties And Licenses [Line Items]
Royalty-related assets	$ 34	$ 39