Segment Information and Major Customers (Summary Of Net Sales For Groups Of Similar Products And Services) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 28, 2012	Jul. 30, 2011	Jul. 31, 2010
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ 46,061	$ 43,218	$ 40,040
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	9,735	8,692	7,620
Sales Revenue, Product Line | Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	14,531	14,130	14,074
Sales Revenue, Product Line | NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	8,425	8,264	7,868
Sales Revenue, Product Line | Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	4,139	4,013	2,981
Sales Revenue, Product Line | Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	3,858	3,483	3,294
Sales Revenue, Product Line | Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	1,699	1,427	1,134
Sales Revenue, Product Line | Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	1,349	1,200	1,302
Sales Revenue, Product Line | Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	1,298	694	196
Sales Revenue, Product Line | Other products
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	1,027	1,315	1,571
Sales Revenue, Product Line | Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ 36,326	$ 34,526	$ 32,420