Balance Sheet Details (Details) - USD ($) $ in Millions	Jan. 26, 2019	Jul. 29, 2018	Jul. 28, 2018
Total cash, cash equivalents, and restricted cash
Cash and cash equivalents	$ 9,835		$ 8,934
Restricted cash included in other current assets	23		32
Restricted cash included in other assets	21		27
Total cash, cash equivalents, and restricted cash	9,879		8,993
Inventories:
Raw materials	468		423
Finished goods:
Deferred cost of sales and distributor inventory	74		443
Manufactured finished goods	908		689
Total finished goods	982		1,132
Service-related spares	228		258
Demonstration systems	23		33
Total	1,701	$ 1,544	1,846
Gross property and equipment:
Land, buildings, and building and leasehold improvements	4,731		4,710
Computer equipment and related software	965		1,085
Production, engineering, and other equipment	5,616		5,734
Operating lease assets	529		356
Furniture and fixtures	369		358
Total gross property and equipment	12,210		12,243
Less: accumulated depreciation and amortization	(9,279)		(9,237)
Total	2,931		3,006
Disaggregation of Revenue [Line Items]
Deferred revenue:	17,261		19,685
Current	9,976	9,788	11,490
Noncurrent	7,285	$ 7,114	8,195
Service
Disaggregation of Revenue [Line Items]
Deferred revenue:	11,246		11,431
Product
Disaggregation of Revenue [Line Items]
Deferred revenue:	$ 6,015		$ 8,254