Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 25, 2025	Oct. 26, 2024
Disaggregation of Revenue [Line Items]
Revenue	$ 14,883	$ 13,841
Product
Disaggregation of Revenue [Line Items]
Revenue	11,077	10,114
Networking
Disaggregation of Revenue [Line Items]
Revenue	7,768	6,753
Security
Disaggregation of Revenue [Line Items]
Revenue	1,980	2,017
Collaboration
Disaggregation of Revenue [Line Items]
Revenue	1,055	1,085
Observability
Disaggregation of Revenue [Line Items]
Revenue	274	258
Services
Disaggregation of Revenue [Line Items]
Revenue	3,806	3,727
Subscription
Disaggregation of Revenue [Line Items]
Revenue	8,000	7,844
Subscription Revenue, Product
Disaggregation of Revenue [Line Items]
Revenue	4,500	4,419
Subscription Revenue, Service
Disaggregation of Revenue [Line Items]
Revenue	$ 3,500	$ 3,425