Business Combinations (Summary Of Allocation Of Total Purchase Consideration) (Detail) (USD $) In Millions, unless otherwise specified	Jul. 28, 2012	Jul. 30, 2011	Jul. 31, 2010
Business Acquisition [Line Items]
Purchase Consideration	$ 398	$ 288	$ 6,186
Net Tangible Assets Acquired/ (Liabilities Assumed)	(39)	(10)	4
Purchased Intangible Assets	200	114	2,380
Goodwill	237	184	3,802
Lightwire, Inc.
Business Acquisition [Line Items]
Purchase Consideration	239
Net Tangible Assets Acquired/ (Liabilities Assumed)	(15)
Purchased Intangible Assets	97
Goodwill	157
All Others
Business Acquisition [Line Items]
Purchase Consideration	159		128
Net Tangible Assets Acquired/ (Liabilities Assumed)	(24)		2
Purchased Intangible Assets	103		95
Goodwill	80		31
ScanSafe, Inc.
Business Acquisition [Line Items]
Purchase Consideration			154
Net Tangible Assets Acquired/ (Liabilities Assumed)			2
Purchased Intangible Assets			31
Goodwill			121
Starent Networks, Corp.
Business Acquisition [Line Items]
Purchase Consideration			2,636
Net Tangible Assets Acquired/ (Liabilities Assumed)			(17)
Purchased Intangible Assets			1,274
Goodwill			1,379
Tandberg ASA
Business Acquisition [Line Items]
Purchase Consideration			3,268
Net Tangible Assets Acquired/ (Liabilities Assumed)			17
Purchased Intangible Assets			980
Goodwill			$ 2,271