Balance Sheet and Other Details (Details) - USD ($) $ in Millions	Jan. 23, 2021	Jul. 25, 2020	Jan. 25, 2020	Jul. 27, 2019
Cash, cash equivalents, and restricted cash:
Cash and cash equivalents	$ 11,793	$ 11,809
Restricted cash included in other current assets	7	0
Restricted cash included in other assets	3	3
Total cash, cash equivalents, and restricted cash	11,803	11,812	$ 8,499	$ 11,772
Inventories:
Raw materials	527	456
Work in process	30	25
Finished goods:
Deferred cost of sales	74	59
Manufactured finished goods	600	542
Total finished goods	674	601
Service-related spares	191	184
Demonstration systems	14	16
Total	1,436	1,282
Property, Plant and Equipment [Line Items]
Total gross property and equipment	11,066	11,014
Less: accumulated depreciation and amortization	(8,680)	(8,561)
Total	2,386	2,453
Deferred revenue:
Deferred revenue:	20,846	20,446
Current	11,552	11,406
Noncurrent	9,294	9,040
Remaining Performance Obligations:
Remaining performance obligation	28,178	28,354
Product
Deferred revenue:
Deferred revenue:	8,332	7,895
Remaining Performance Obligations:
Remaining performance obligation	11,666	11,261
Service
Deferred revenue:
Deferred revenue:	12,514	12,551
Remaining Performance Obligations:
Remaining performance obligation	16,512	17,093
Land, buildings, and building and leasehold improvements
Property, Plant and Equipment [Line Items]
Total gross property and equipment	4,291	4,252
Computer equipment and related software
Property, Plant and Equipment [Line Items]
Total gross property and equipment	864	875
Production, engineering, and other equipment
Property, Plant and Equipment [Line Items]
Total gross property and equipment	5,193	5,163
Operating lease assets
Property, Plant and Equipment [Line Items]
Total gross property and equipment	343	337
Less: accumulated depreciation and amortization	(201)	(198)
Total	142	139
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Total gross property and equipment	$ 375	$ 387