Segment Information and Major Customers (Summary Of Net Revenue For Groups Of Similar Products And Services) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 25, 2015	Jul. 26, 2014	Jul. 27, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	$ 49,161	$ 47,142	$ 48,607
Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	14,741	14,001	14,711
NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	7,704	7,609	8,168
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	4,000	3,815	4,057
Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	3,555	3,969	4,855
Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	3,220	2,640	2,074
Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	2,542	2,293	2,257
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	1,747	1,566	1,348
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	241	279	559
Product:
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	37,750	36,172	38,029
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue:	$ 11,411	$ 10,970	$ 10,578