Goodwill and Purchased Intangible Assets (Schedule of Amortization of Purchased Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 39	$ 60	$ 73	$ 121
Cost of sales
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	156	160	307	314
Share-based compensation expense in operating expenses
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	39	60	73	121
Total
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 195	$ 220	$ 380	$ 435