Segment Information and Major Customers - Summary of Net Revenue for Groups of Similar Products and Services (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 26, 2019	Oct. 27, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	$ 13,159	$ 13,072
Discontinued operations, held-for-sale | Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total		168
Infrastructure Platforms
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	7,538	7,622
Applications
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	1,499	1,419
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	815	670
Other Products
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	26	178
Other Products | Discontinued operations, held-for-sale | Service Provider Video
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	168
Total Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	9,878	9,890
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue, total	$ 3,281	$ 3,182