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. 23, 2016	Jan. 24, 2015	Jan. 23, 2016	Jan. 24, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		$ 11,927	$ 11,936	$ 24,609	$ 24,181
Switching
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		3,483	3,615	7,505	7,461
NGN Routing
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		1,845	1,764	3,638	3,713
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		1,019	991	2,134	1,941
Data Center
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		822	846	1,681	1,538
Service Provider Video (1)
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	[1]	662	776	1,512	1,647
Wireless
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		613	611	1,258	1,216
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		462	416	947	871
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		77	59	152	126
Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		8,983	9,078	18,827	18,513
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue		$ 2,944	$ 2,858	$ 5,782	$ 5,668

[1] Includes SP Video CPE Business revenue of $93 million (one month of operations) and $361 million for the second quarter of fiscal 2016 and 2015, respectively and $504 million and $840 million for the first six months of fiscal 2016 and 2015, respectively.