Segment Information and Major Customers (Summary Of Net Revenue For Groups Of Similar Products And Services) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 26, 2014	Jul. 27, 2013	Jul. 28, 2012
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	$ 47,142	$ 48,607	$ 46,061
Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	14,056	14,767	14,634
NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	7,662	8,243	8,395
Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	3,969	4,855	3,869
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	3,734	3,956	4,194
Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	2,640	2,074	1,298
Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	2,265	2,228	1,697
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	1,566	1,348	1,341
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	280	558	898
Product:
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	36,172	38,029	36,326
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	$ 10,970	$ 10,578	$ 9,735