Recent Accounting Pronouncements (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 27, 2019	Apr. 28, 2018	Apr. 27, 2019	Apr. 28, 2018	Jul. 29, 2018	Jul. 28, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, total	$ 12,958	$ 12,463	$ 38,476	$ 36,486
Benefit for provision for income taxes	(571)	$ (562)	(1,452)	$ (13,140)
Increase in retained earnings	(2,877)		(2,877)		$ 5,130	$ 1,233
Total contract assets noncurrent	383		383
Total capitalized contract acquisition costs	705		705			644
Capitalized contract acquisition costs, current	390		390
Capitalized contract acquisition costs, noncurrent	315		315
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in retained earnings					2,333
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, total	146		662
Benefit for provision for income taxes	152		152
Increase in retained earnings					$ 2,300
Software and Service Agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total contract assets	637		637			$ 122
Total contract assets, current	$ 254		$ 254