Restructuring Charges - Activities Related to Restructuring Reserves (Detail) - USD ($) $ in Millions	3 Months Ended
	Jul. 31, 2020	Jul. 26, 2019
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	$ 1	$ 19
Net charges	5	21
Cash payments	(5)	(20)
Other	0	(4)
Balance at end of period	1	16
May 2020 Restructuring
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	0
Net charges	5
Cash payments	(5)
Other	0
Balance at end of period	0
May 2019 Restructuring
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	1	0
Net charges	0	21
Cash payments	0	(11)
Other	0	0
Balance at end of period	1	10
April 2019 Restructuring
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period	0	15
Net charges	0	0
Cash payments	0	(9)
Other	0	0
Balance at end of period	$ 0	6
November 2016 Restructuring
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		4
Net charges		0
Cash payments		0
Other		(4)
Balance at end of period		$ 0