Goodwill and Purchased Intangible Assets - Schedule of Amortization of Purchased Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 25, 2020	Jan. 26, 2019	Jan. 25, 2020	Jan. 26, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 38	$ 39	$ 74	$ 73
Total
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	203	195	405	380
Cost of sales
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	165	156	331	307
Operating expenses
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 38	$ 39	$ 74	$ 73