Balance Sheet Details (Details) - USD ($) $ in Millions	Jan. 25, 2020	Jul. 27, 2019	Jan. 26, 2019	Jul. 28, 2018
Total cash, cash equivalents, and restricted cash
Cash and cash equivalents	$ 8,475	$ 11,750
Restricted cash included in other current assets	21	21
Restricted cash included in other assets	3	1
Total cash, cash equivalents, and restricted cash	8,499	11,772	$ 9,879	$ 8,993
Inventories:
Raw materials	384	374
Work in process	12	10
Finished goods:
Deferred cost of sales	59	109
Manufactured finished goods	667	643
Total finished goods	726	752
Service-related spares	212	225
Demonstration systems	19	22
Total	1,353	1,383
Property and equipment, net:
Total gross property and equipment	11,337	12,039
Less: accumulated depreciation and amortization	(8,716)	(9,250)
Total	2,621	2,789
Disaggregation of Revenue [Line Items]
Deferred revenue:	18,686	18,467
Current	10,638	10,668
Noncurrent	8,048	7,799
Land, buildings, and building and leasehold improvements
Property and equipment, net:
Total gross property and equipment	4,438	4,545
Computer equipment and related software
Property and equipment, net:
Total gross property and equipment	900	922
Production, engineering, and other equipment
Property and equipment, net:
Total gross property and equipment	5,196	5,711
Operating lease assets
Property and equipment, net:
Total gross property and equipment	411
Less: accumulated depreciation and amortization	(247)
Total	164
Operating lease assets
Property and equipment, net:
Total gross property and equipment		485
Furniture, fixtures and other
Property and equipment, net:
Total gross property and equipment	392	376
Service
Disaggregation of Revenue [Line Items]
Deferred revenue:	11,526	11,709
Product
Disaggregation of Revenue [Line Items]
Deferred revenue:	$ 7,160	$ 6,758