Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 28, 2023	Jan. 29, 2022	Jan. 28, 2023	Jan. 29, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 13,592	$ 12,720	$ 27,224	$ 25,620
Product
Disaggregation of Revenue [Line Items]
Revenue	10,155	9,353	20,400	18,882
Secure, Agile Networks
Disaggregation of Revenue [Line Items]
Revenue	6,746	5,899	13,430	11,867
Internet for the Future
Disaggregation of Revenue [Line Items]
Revenue	1,306	1,322	2,616	2,695
Collaboration
Disaggregation of Revenue [Line Items]
Revenue	958	1,067	2,044	2,176
End-to-End Security
Disaggregation of Revenue [Line Items]
Revenue	943	883	1,914	1,778
Optimized Application Experiences
Disaggregation of Revenue [Line Items]
Revenue	199	180	393	361
Other Products
Disaggregation of Revenue [Line Items]
Revenue	3	2	4	5
Services
Disaggregation of Revenue [Line Items]
Revenue	$ 3,437	$ 3,367	$ 6,824	$ 6,738