Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 29, 2023	Jul. 30, 2022	Jul. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 56,998	$ 51,557	$ 49,818
Product
Disaggregation of Revenue [Line Items]
Total revenue	43,142	38,018	36,014
Secure, Agile Networks
Disaggregation of Revenue [Line Items]
Total revenue	29,105	23,831	22,725
Internet for the Future
Disaggregation of Revenue [Line Items]
Total revenue	5,306	5,276	4,511
Collaboration
Disaggregation of Revenue [Line Items]
Total revenue	4,052	4,472	4,727
End-to-End Security
Disaggregation of Revenue [Line Items]
Total revenue	3,859	3,699	3,382
Optimized Application Experiences
Disaggregation of Revenue [Line Items]
Total revenue	811	729	654
Other Products
Disaggregation of Revenue [Line Items]
Total revenue	9	11	15
Service
Disaggregation of Revenue [Line Items]
Total revenue	$ 13,856	$ 13,539	$ 13,804