Goodwill and Purchased Intangible Assets - Schedule of Amortization of Purchased Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 25, 2020	Apr. 27, 2019	Apr. 25, 2020	Apr. 27, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 34	$ 39	$ 108	$ 112
Total
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	197	196	602	576
Cost of sales
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	163	157	494	464
Operating expenses
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 34	$ 39	$ 108	$ 112