Segment Information and Major Customers (Summary of Net Revenue for Groups of Similar Products and Services) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jul. 28, 2018	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 12,844	$ 12,463	$ 11,887	$ 12,136	$ 12,133	$ 11,940	$ 11,580	$ 12,352	$ 49,330	$ 48,005	$ 49,247
Infrastructure Platforms
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									28,270	27,779	28,851
Applications
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									5,035	4,568	4,438
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									2,353	2,153	1,969
Other Products
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									1,050	1,205	1,996
Product:
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									36,709	35,705	37,254
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									$ 12,621	$ 12,300	11,993
SP Video CPE Business
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue											$ 504