Revenue - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 25, 2020	Apr. 27, 2019	Apr. 25, 2020	Apr. 27, 2019	Jul. 27, 2019
Revenue from Contract with Customer [Abstract]
Payment terms			30 days
Accounts receivable, net	$ 4,569		$ 4,569		$ 5,491
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	25,500		25,500		25,300
Total deferred revenue	18,648		18,648		18,467
Revenue recognized	2,300		8,900
Total deferred sales commissions	703		703		750
Amortization of sales commissions, expense	118	$ 124	356	$ 349
Unbilled Contract Revenue
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	6,900		6,900		6,800
Software and Service Agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total contract assets	$ 1,100		$ 1,100		$ 860