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. 27, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 28, 2018	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 27, 2019	Jul. 28, 2018	Jul. 29, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 13,428	$ 12,958	$ 12,446	$ 13,072	$ 12,844	$ 12,463	$ 11,887	$ 12,136	$ 51,904	$ 49,330	$ 48,005
Infrastructure Platforms
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									30,191	28,322	27,817
Applications
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									5,803	5,036	4,568
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									2,730	2,352	2,152
Other Products
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									281	999	1,168
Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									39,005	36,709	35,705
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									12,899	12,621	$ 12,300
SPVSS Business
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									$ 168	$ 903