Revenue - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 24, 2020	Oct. 26, 2019	Jul. 25, 2020
Disaggregation of Revenue [Line Items]
Allowance for future sales returns	$ 81		$ 79
Payment terms	30 days
Accounts receivable, net	$ 3,980		5,472
Deferred revenue	20,473		20,446
Revenue recognized	3,900
Total deferred sales commissions	771		732
Amortization of sales commissions, expense	123	$ 116
Software and Service Agreements
Disaggregation of Revenue [Line Items]
Total contract assets	$ 1,200		$ 1,200