Segment Information and Major Customers (Summary Of Net Revenue For Groups Of Similar Products And Services) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 28, 2017	Jan. 23, 2016	Jan. 28, 2017	Jan. 23, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	$ 11,580	$ 11,927	$ 23,932	$ 24,609
Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	3,305	3,475	7,021	7,484
NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	1,817	2,014	3,906	3,983
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	1,062	1,019	2,143	2,134
Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	790	822	1,624	1,681
Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	632	616	1,264	1,262
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	528	462	1,068	947
Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	241	499	512	1,186
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	116	76	255	150
Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	8,491	8,983	17,793	18,827
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net	$ 3,089	2,944	$ 6,139	5,782
SP Video CPE Business
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, Net		$ 93		$ 504