Balance Sheet and Other Details (Details) - USD ($) $ in Millions	Oct. 24, 2020	Jul. 25, 2020	Oct. 26, 2019	Jul. 27, 2019
Cash, cash equivalents, and restricted cash:
Cash and cash equivalents	$ 10,822	$ 11,809
Restricted cash included in other current assets	3	0
Restricted cash included in other assets	0	3
Total cash, cash equivalents, and restricted cash	10,825	11,812	$ 8,613	$ 11,772
Inventories:
Raw materials	380	456
Work in process	19	25
Finished goods:
Deferred cost of sales	54	59
Manufactured finished goods	646	542
Total finished goods	700	601
Service-related spares	191	184
Demonstration systems	13	16
Total	1,303	1,282
Property, Plant and Equipment [Line Items]
Total gross property and equipment	11,025	11,014
Less: accumulated depreciation and amortization	(8,613)	(8,561)
Total	2,412	2,453
Deferred revenue:
Deferred revenue:	20,473	20,446
Current	11,271	11,406
Noncurrent	9,202	9,040
Remaining Performance Obligations:
Remaining performance obligation	27,469	28,354
Product
Deferred revenue:
Deferred revenue:	8,139	7,895
Remaining Performance Obligations:
Remaining performance obligation	11,340	11,261
Service
Deferred revenue:
Deferred revenue:	12,334	12,551
Remaining Performance Obligations:
Remaining performance obligation	16,129	17,093
Land, buildings, and building and leasehold improvements
Property, Plant and Equipment [Line Items]
Total gross property and equipment	4,273	4,252
Computer equipment and related software
Property, Plant and Equipment [Line Items]
Total gross property and equipment	872	875
Production, engineering, and other equipment
Property, Plant and Equipment [Line Items]
Total gross property and equipment	5,157	5,163
Operating lease assets
Property, Plant and Equipment [Line Items]
Total gross property and equipment	338	337
Less: accumulated depreciation and amortization	(200)	(198)
Total	138	139
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Total gross property and equipment	$ 385	$ 387