Summary of Significant Accounting Policies - Summary of Cumulative Effect of the Changes Made to Consolidated Balance Sheet for the Adoption of New Accounting Standard Updates (Details) - USD ($) $ in Millions	Jul. 27, 2019	Jul. 29, 2018	Jul. 28, 2018
ASSETS
Accounts receivable, net	$ 5,491	$ 5,450	$ 5,554
Inventories	1,383	1,544	1,846
Other current assets	2,373	3,286	2,940
Deferred tax assets	4,065	3,995	3,219
Other assets	2,496	1,954	1,582
TOTAL ASSETS	97,793	109,872	108,784
LIABILITIES AND EQUITY
Income taxes payable	1,149	1,015	1,004
Deferred revenue	10,668	9,788	11,490
Other current liabilities	4,424	4,446	4,413
Deferred revenue	7,799	7,114	8,195
Other long-term liabilities	1,309	1,532	1,434
(Accumulated deficit) Retained earnings	(5,903)	5,130	1,233
Accumulated other comprehensive income (loss)	(792)	(1,017)	(849)
TOTAL LIABILITIES AND EQUITY	97,793	109,872	108,784
Total deferred revenue	18,467		19,685
Product
LIABILITIES AND EQUITY
Total deferred revenue	6,758		$ 8,254
Accounting Standards Update 2014-09
ASSETS
Accounts receivable, net		(104)
Inventories		(302)
Other current assets		371
Deferred tax assets		(624)
Other assets		327
TOTAL ASSETS		(332)
LIABILITIES AND EQUITY
Income taxes payable		0
Deferred revenue		(1,702)
Other current liabilities		33
Deferred revenue		(1,081)
Other long-term liabilities		85
(Accumulated deficit) Retained earnings		2,333
Accumulated other comprehensive income (loss)		0
TOTAL LIABILITIES AND EQUITY		(332)
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
LIABILITIES AND EQUITY
(Accumulated deficit) Retained earnings		2,300
Total deferred revenue	$ 2,800	2,800
Accounting Standards Update 2014-09 | Product | Difference between Revenue Guidance in Effect before and after Topic 606
LIABILITIES AND EQUITY
Total deferred revenue		2,600
Accounting Standards Update 2014-09 | Recurring software and subscription offers | Difference between Revenue Guidance in Effect before and after Topic 606
LIABILITIES AND EQUITY
Total deferred revenue		1,300
Accounting Standards Update 2014-09 | Two-tier distribution | Difference between Revenue Guidance in Effect before and after Topic 606
LIABILITIES AND EQUITY
Total deferred revenue		600
Accounting Standards Update 2016-01
ASSETS
Accounts receivable, net		0
Inventories		0
Other current assets		0
Deferred tax assets		(15)
Other assets		136
TOTAL ASSETS		121
LIABILITIES AND EQUITY
Income taxes payable		0
Deferred revenue		0
Other current liabilities		0
Deferred revenue		0
Other long-term liabilities		13
(Accumulated deficit) Retained earnings		283
Accumulated other comprehensive income (loss)		(175)
TOTAL LIABILITIES AND EQUITY		121
Accounting Standards Update 2016-16
ASSETS
Accounts receivable, net		0
Inventories		0
Other current assets		(25)
Deferred tax assets		1,415
Other assets		(91)
TOTAL ASSETS		1,299
LIABILITIES AND EQUITY
Income taxes payable		11
Deferred revenue		0
Other current liabilities		0
Deferred revenue		0
Other long-term liabilities		0
(Accumulated deficit) Retained earnings		1,281
Accumulated other comprehensive income (loss)		7
TOTAL LIABILITIES AND EQUITY		$ 1,299