Fair Value Measurements (Financial Assets Measured At Fair Value On A Recurring and Nonrecurring Basis) (Details) - USD ($) $ in Millions	Apr. 29, 2017	Apr. 30, 2016
Marketable equity and debt securities	$ 90	$ 125
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Marketable equity and debt securities	21	17
Significant Observable Inputs (Level 2) [Member]
Marketable equity and debt securities	69	108
Significant Unobservable Inputs (Level 3) [Member]
Marketable equity and debt securities	$ 0	$ 0