Balance Sheet Details (Details) - USD ($) $ in Millions	Jul. 27, 2019	Jul. 29, 2018	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Cash, Cash Equivalents, and Restricted Cash [Abstract]
Cash and cash equivalents	$ 11,750		$ 8,934
Restricted cash included in other current assets	21		32
Restricted cash included in other assets	1		27
Total cash, cash equivalents, and restricted cash	11,772		8,993	$ 11,773	$ 7,739
Inventories:
Raw materials	374		423
Work in process	10		0
Finished goods:
Deferred cost of sales and distributor inventory	109		443
Manufactured finished goods	643		689
Total finished goods	752		1,132
Service-related spares	225		258
Demonstration systems	22		33
Total	1,383	$ 1,544	1,846
Gross property and equipment:
Land, buildings, and building and leasehold improvements	4,545		4,710
Computer equipment and related software	922		1,085
Production, engineering, and other equipment	5,711		5,734
Operating lease assets	485		356
Furniture and fixtures	376		358
Total gross property and equipment	12,039		12,243
Less: accumulated depreciation and amortization	(9,250)		(9,237)
Total	2,789		3,006	$ 3,322
Deferred Revenue Arrangement [Line Items]
Deferred revenue	18,467		19,685
Current	10,668	9,788	11,490
Noncurrent	7,799	$ 7,114	8,195
Service
Deferred Revenue Arrangement [Line Items]
Deferred revenue	11,709		11,431
Product
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 6,758		$ 8,254