Acquisitions and Divestitures (Summary Of Allocation Of Total Purchase Consideration) (Details) $ in Millions	3 Months Ended	9 Months Ended
	Apr. 29, 2017 USD ($) acquisition	Apr. 29, 2017 USD ($) acquisition
Business Acquisition [Line Items]
Number of business combinations | acquisition		4
Purchase Consideration		$ 3,516
Net Tangible Assets Acquired (Liabilities Assumed)	$ (175)	(175)
Purchased Intangible Assets	826	826
Goodwill	2,865	2,865
CloudLock
Business Acquisition [Line Items]
Purchase Consideration		249
Net Tangible Assets Acquired (Liabilities Assumed)	0	0
Purchased Intangible Assets	36	36
Goodwill	213	213
AppDynamics
Business Acquisition [Line Items]
Purchase Consideration		3,258
Net Tangible Assets Acquired (Liabilities Assumed)	(175)	(175)
Purchased Intangible Assets	785	785
Goodwill	$ 2,648	$ 2,648
Others (two in total)
Business Acquisition [Line Items]
Number of business combinations | acquisition	2	2
Purchase Consideration		$ 9
Net Tangible Assets Acquired (Liabilities Assumed)	$ 0	0
Purchased Intangible Assets	5	5
Goodwill	$ 4	$ 4