Segment Information and Major Customers - Summary of Net Revenue for Groups of Similar Products and Services (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 30, 2022	Jul. 31, 2021	Jul. 25, 2020
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	$ 51,557	$ 49,818	$ 49,301
Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	38,018	36,014	35,978
Secure, Agile Networks
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	23,829	22,722	23,265
Internet for the Future
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	5,278	4,514	4,180
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	4,472	4,727	4,823
End-to-End Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	3,699	3,382	3,158
Optimized Application Experiences
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	729	654	524
Other Products
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	11	15	28
Service
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	$ 13,539	$ 13,804	$ 13,323