Balance Sheet Details (Details) - USD ($) $ in Millions	Oct. 26, 2019	Jul. 27, 2019	Oct. 27, 2018	Jul. 28, 2018
Total cash, cash equivalents, and restricted cash
Cash and cash equivalents	$ 8,587	$ 11,750
Restricted cash included in other current assets	23	21
Restricted cash included in other assets	3	1
Total cash, cash equivalents, and restricted cash	8,613	11,772	$ 8,486	$ 8,993
Inventories:
Raw materials	424	374
Work in process	9	10
Finished goods:
Deferred cost of sales	87	109
Manufactured finished goods	576	643
Total finished goods	663	752
Service-related spares	226	225
Demonstration systems	22	22
Total	1,344	1,383
Property and equipment, net:
Total gross property and equipment	11,811	12,039
Less: accumulated depreciation and amortization	(9,142)	(9,250)
Total	2,669	2,789
Disaggregation of Revenue [Line Items]
Deferred revenue:	18,602	18,467
Current	10,646	10,668
Noncurrent	7,956	7,799
Land, buildings, and building and leasehold improvements
Property and equipment, net:
Total gross property and equipment	4,413	4,545
Computer equipment and related software
Property and equipment, net:
Total gross property and equipment	908	922
Production, engineering, and other equipment
Property and equipment, net:
Total gross property and equipment	5,668	5,711
Operating lease assets
Property and equipment, net:
Total gross property and equipment	438
Less: accumulated depreciation and amortization	(274)
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	384	376
Service
Disaggregation of Revenue [Line Items]
Deferred revenue:	11,497	11,709
Product
Disaggregation of Revenue [Line Items]
Deferred revenue:	$ 7,105	$ 6,758