Segment Information And Major Customers (Net Sales For Groups Of Similar Products And Services) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 27, 2012	Oct. 29, 2011
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 11,876	$ 11,256
Service [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	2,579	2,304
Sales Revenue, Product Line [Member] | Switching [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	3,616	3,687
Sales Revenue, Product Line [Member] | Next Generation Networks [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	2,052	2,094
Sales Revenue, Product Line [Member] | Service Provider Video [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	1,148	883
Sales Revenue, Product Line [Member] | Collaboration [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	1,020	1,108
Sales Revenue, Product Line [Member] | Wireless [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	486	353
Sales Revenue, Product Line [Member] | Data Center [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	417	259
Sales Revenue, Product Line [Member] | Security [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	338	319
Sales Revenue, Product Line [Member] | Other Products [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	220	249
Sales Revenue, Product Line [Member] | Product [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 9,297	$ 8,952