Segment Information and Major Customers - Summary of Net Revenue for Groups of Similar Products and Services (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 25, 2025	Jan. 27, 2024	Jan. 25, 2025	Jan. 27, 2024
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 13,991	$ 12,791	$ 27,832	$ 27,459
Total Product
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	10,234	9,232	20,348	20,371
Networking
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	6,850	7,081	13,603	15,904
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	2,111	973	4,129	1,984
Collaboration
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	996	989	2,081	2,106
Observability
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	277	188	535	378
Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 3,757	$ 3,559	$ 7,484	$ 7,088