Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 27, 2024	Jan. 28, 2023	Jan. 27, 2024	Jan. 28, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 12,791	$ 13,592	$ 27,459	$ 27,224
Product
Disaggregation of Revenue [Line Items]
Revenue	9,232	10,155	20,371	20,400
Networking
Disaggregation of Revenue [Line Items]
Revenue	7,081	8,092	15,904	16,123
Security
Disaggregation of Revenue [Line Items]
Revenue	973	943	1,984	1,914
Collaboration
Disaggregation of Revenue [Line Items]
Revenue	989	958	2,106	2,044
Observability
Disaggregation of Revenue [Line Items]
Revenue	188	162	378	319
Services
Disaggregation of Revenue [Line Items]
Revenue	$ 3,559	$ 3,437	$ 7,088	$ 6,824