Acquisitions and Divestitures (Summary Of Allocation Of Total Purchase Consideration) (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jan. 28, 2017 USD ($) acquisition	Jan. 28, 2017 USD ($) acquisition
Business Acquisition [Line Items]
Number of business combinations | acquisition		3
Purchase Consideration		$ 258
Purchased Intangible Assets	$ 41	41
Goodwill	217	217
CloudLock Inc
Business Acquisition [Line Items]
Purchase Consideration		249
Purchased Intangible Assets	36	36
Goodwill	$ 213	$ 213
Others (two in total)
Business Acquisition [Line Items]
Number of business combinations | acquisition	2	2
Purchase Consideration		$ 9
Purchased Intangible Assets	$ 5	5
Goodwill	$ 4	$ 4