Segment Information And Major Customers (Net Sales For Groups Of Similar Products And Services) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 26, 2014	Apr. 27, 2013	Apr. 26, 2014	Apr. 27, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 11,545	$ 12,216	$ 34,785	$ 36,190
Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	3,381	3,601	10,406	10,962
NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	1,935	2,145	5,719	6,147
Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	961	1,299	2,905	3,670
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	892	1,013	2,800	2,978
Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	662	515	1,868	1,480
Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	553	539	1,604	1,573
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	361	327	1,119	1,002
Other Products
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	75	120	219	481
Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	8,820	9,559	26,640	28,293
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 2,725	$ 2,657	$ 8,145	$ 7,897