Recent Accounting Pronouncements (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018	Jul. 29, 2018	Jul. 28, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, total	$ 12,446	$ 11,887	$ 25,518	$ 24,023
Benefit for provision for income taxes	(521)	$ (12,010)	(881)	$ (12,578)
Increase in retained earnings	538		538		$ 5,130	$ 1,233
Total contract assets	5,200		5,200
Total contract assets noncurrent	316		316
Total capitalized contract acquisition costs	686		686			644
Capitalized contract acquisition costs, current	380		380
Capitalized contract acquisition costs, noncurrent	306		306
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	267		516
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	557		557			$ 122
Total contract assets, current	$ 241		$ 241