Goodwill and Purchased Intangible Assets (Schedule of Amortization of Purchased Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 27, 2018	Oct. 28, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 34	$ 61
Cost of sales
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	151	154
Share-based compensation expense in operating expenses
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	34	61
Total
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 185	$ 215