Segment Information and Major Customers (Summary Of Net Revenue For Groups Of Similar Products And Services) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 25, 2014	Oct. 26, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 12,245	$ 12,085
Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	3,846	3,740
NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	1,949	2,026
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	949	1,051
Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	871	987
Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	693	601
Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	605	547
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	455	365
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	67	80
Product:
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	9,435	9,397
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 2,810	$ 2,688