Balance Sheet Details (Details) - USD ($) $ in Millions	Apr. 25, 2020	Jul. 27, 2019	Apr. 27, 2019	Jul. 28, 2018
Total cash, cash equivalents, and restricted cash
Cash and cash equivalents	$ 10,366	$ 11,750
Restricted cash included in other current assets	1	21
Restricted cash included in other assets	3	1
Total cash, cash equivalents, and restricted cash	10,370	11,772	$ 10,273	$ 8,993
Inventories:
Raw materials	446	374
Work in process	20	10
Finished goods:
Deferred cost of sales	57	109
Manufactured finished goods	492	643
Total finished goods	549	752
Service-related spares	182	225
Demonstration systems	15	22
Total	1,212	1,383
Property and equipment, net:
Total gross property and equipment	11,137	12,039
Less: accumulated depreciation and amortization	(8,602)	(9,250)
Total	2,535	2,789
Disaggregation of Revenue [Line Items]
Deferred revenue:	18,648	18,467
Current	10,710	10,668
Noncurrent	7,938	7,799
Land, buildings, and building and leasehold improvements
Property and equipment, net:
Total gross property and equipment	4,405	4,545
Computer equipment and related software
Property and equipment, net:
Total gross property and equipment	895	922
Production, engineering, and other equipment
Property and equipment, net:
Total gross property and equipment	5,093	5,711
Operating lease assets
Property and equipment, net:
Total gross property and equipment	348
Less: accumulated depreciation and amortization	(197)
Total	151
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	396	376
Service
Disaggregation of Revenue [Line Items]
Deferred revenue:	11,423	11,709
Product
Disaggregation of Revenue [Line Items]
Deferred revenue:	$ 7,225	$ 6,758