Acquisitions and Divestitures - Summary of Allocation of Total Purchase Consideration (Details) $ in Millions	12 Months Ended
	Jul. 25, 2020 USD ($) acquisition	Jul. 27, 2019 USD ($) acquisition	Jul. 28, 2018 USD ($) acquisition
Business Acquisition [Line Items]
Number of business combinations (acquisition) | acquisition	6		8
Purchase Consideration	$ 359	$ 2,686	$ 3,200
Net Tangible Assets Acquired (Liabilities Assumed)	(11)	(74)
Purchased Intangible Assets	172	672
Goodwill	$ 198	2,088
Duo
Business Acquisition [Line Items]
Purchase Consideration		2,025
Net Tangible Assets Acquired (Liabilities Assumed)		(57)
Purchased Intangible Assets		342
Goodwill		1,740
Luxtera
Business Acquisition [Line Items]
Purchase Consideration		596
Net Tangible Assets Acquired (Liabilities Assumed)		(19)
Purchased Intangible Assets		319
Goodwill		$ 296
Others
Business Acquisition [Line Items]
Number of business combinations (acquisition) | acquisition		3
Purchase Consideration		$ 65
Net Tangible Assets Acquired (Liabilities Assumed)		2
Purchased Intangible Assets		11
Goodwill		$ 52