Balance Sheet Details (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 25, 2020	Jul. 27, 2019	Jul. 28, 2018	Jul. 29, 2017
Cash, Cash Equivalents, and Restricted Cash:
Cash and cash equivalents	$ 11,809	$ 11,750
Restricted cash included in other current assets	0	21
Restricted cash included in other assets	3	1
Total cash, cash equivalents, and restricted cash	11,812	11,772	$ 8,993	$ 11,773
Inventories:
Raw materials	456	374
Work in process	25	10
Finished goods:
Deferred cost of sales	59	109
Manufactured finished goods	542	643
Total finished goods	601	752
Service-related spares	184	225
Demonstration systems	16	22
Total	1,282	1,383
Provision for inventory	74	77	$ 63
Property, Plant and Equipment [Line Items]
Total gross property and equipment	11,014	12,039
Less: accumulated depreciation and amortization	(8,561)	(9,250)
Total	2,453	2,789
Deferred Revenue Arrangement [Line Items]
Deferred revenue	20,446	18,467
Current	11,406	10,668
Noncurrent	9,040	7,799
Disaggregation of Revenue [Line Items]
Remaining performance obligation	28,354	25,305
Service
Deferred Revenue Arrangement [Line Items]
Deferred revenue	12,551	11,709
Disaggregation of Revenue [Line Items]
Remaining performance obligation	17,093	15,702
Product
Deferred Revenue Arrangement [Line Items]
Deferred revenue	7,895	6,758
Disaggregation of Revenue [Line Items]
Remaining performance obligation	11,261	9,603
Land, buildings, and building and leasehold improvements
Property, Plant and Equipment [Line Items]
Total gross property and equipment	4,252	4,545
Computer equipment and related software
Property, Plant and Equipment [Line Items]
Total gross property and equipment	875	922
Production, engineering, and other equipment
Property, Plant and Equipment [Line Items]
Total gross property and equipment	5,163	5,711
Operating lease assets
Property, Plant and Equipment [Line Items]
Total gross property and equipment	337	485
Less: accumulated depreciation and amortization	(198)
Total	139
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Total gross property and equipment	$ 387	$ 376