Employee Benefit Plans - Summary of Stock Option Activity (Details) - $ / shares shares in Millions	12 Months Ended
	Jul. 27, 2019	Jul. 28, 2018	Jul. 29, 2017
Number Outstanding
Beginning balance (in shares)	6	12	73
Assumed from acquisitions (in shares)		3	8
Exercised (in shares)	(4)	(8)	(14)
Canceled/forfeited/expired (in shares)		(1)	(55)
Ending balance (in shares)	2	6	12
Weighted-Average Exercise Price per Share
Beginning balance (in dollars per share)	$ 7.18	$ 6.15	$ 26.78
Assumed from acquisitions (in dollars per share)		8.20	4.47
Exercised (in dollars per share)	7.12	5.77	12.11
Canceled/forfeited/expired (in dollars per share)		8.75	31.83
Ending balance (in dollars per share)	$ 6.94	$ 7.18	$ 6.15