Recent Accounting Pronouncements (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 27, 2018	Oct. 28, 2017	Jul. 29, 2018	Jul. 28, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, total	$ 13,072	$ 12,136
Benefit for provision for income taxes	(360)	$ (568)
Increase in retained earnings	3,169		$ 5,130	$ 1,233
Total contract assets	5,500
Total contract assets noncurrent	177
Total capitalized contract acquisition costs	673			644
Capitalized contract acquisition costs, current	380
Capitalized contract acquisition costs, noncurrent	293
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	276
Benefit for provision for income taxes	152
Increase in retained earnings			$ 2,300
Software and Service Agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total contract assets	447			$ 122
Total contract assets, current	$ 270