Segment Information and Major Customers - Summary of Net Revenue for Groups of Similar Products and Services (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 26, 2025	Jul. 27, 2024	Jul. 29, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	$ 56,654	$ 53,803	$ 56,998
Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	41,608	39,253	43,142
Networking
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	28,304	29,229	34,570
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	8,094	5,075	3,859
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	4,154	4,113	4,052
Observability
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	1,055	837	661
Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	$ 15,046	$ 14,550	$ 13,856