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Derivatives and Hedging Activities - Schedule of Derivative Instruments Not Designated as Cash Flow Hedges (Detail) - USD ($)
$ in Millions
12 Months Ended
Apr. 27, 2018
Apr. 28, 2017
Apr. 29, 2016
Foreign Exchange Forward Contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Foreign currency exchange contracts $ (9) $ 1 $ (4)