Acquisitions and Divestitures (Summary of Allocation of Total Purchase Consideration) (Details) $ in Millions	3 Months Ended
	Oct. 27, 2018 USD ($) acquisition
Business Acquisition [Line Items]
Purchase Consideration	$ 2,059
Net Tangible Assets Acquired (Liabilities Assumed)	(54)
Purchased Intangible Assets	350
Goodwill	$ 1,763
Number of business combinations (acquisition) | acquisition	2
Duo
Business Acquisition [Line Items]
Purchase Consideration	$ 2,025
Net Tangible Assets Acquired (Liabilities Assumed)	(57)
Purchased Intangible Assets	342
Goodwill	1,740
Other (one acquisition)
Business Acquisition [Line Items]
Purchase Consideration	34
Net Tangible Assets Acquired (Liabilities Assumed)	3
Purchased Intangible Assets	8
Goodwill	$ 23
Number of business combinations (acquisition) | acquisition	1