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		9 Months Ended
	Apr. 25, 2015	Apr. 26, 2014	Apr. 25, 2015	Apr. 26, 2014
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 12,137	$ 11,545	$ 36,318	$ 34,785
Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	3,560	3,368	11,022	10,366
NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	1,999	1,925	5,712	5,681
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	973	909	2,912	2,859
Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	914	961	2,561	2,905
Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	801	662	2,340	1,868
Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	611	560	1,827	1,624
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	412	361	1,283	1,119
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	56	74	182	218
Product:
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	9,326	8,820	27,839	26,640
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 2,811	$ 2,725	$ 8,479	$ 8,145