Revenue - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2021	Jan. 25, 2020	Jan. 23, 2021	Jan. 25, 2020	Jul. 25, 2020
Disaggregation of Revenue [Line Items]
Allowance for future sales returns	$ 73		$ 73		$ 79
Payment terms			30 days
Accounts receivable, net	4,307		$ 4,307		5,472
Deferred revenue	20,846		20,846		20,446
Revenue recognized	3,000		6,900
Total deferred sales commissions	817		817		732
Amortization of sales commissions, expense	129	$ 122	252	$ 238
Software and Service Agreements
Disaggregation of Revenue [Line Items]
Contract assets, net of allowances	$ 1,300		$ 1,300		$ 1,200