Consolidated Statements of Equity - USD ($) shares in Millions, $ in Millions	Total	Total Equity	Shares of Common Stock	Common Stock and Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Jul. 28, 2018			4,614
Beginning balance at Jul. 28, 2018		$ 43,204		$ 42,820	$ 1,233	$ (849)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)	(109)
Ending balance (in shares) at Oct. 27, 2018			4,517
Ending balance at Oct. 27, 2018		43,848		41,897	3,169	(1,218)
Beginning balance (in shares) at Jul. 28, 2018			4,614
Beginning balance at Jul. 28, 2018		43,204		42,820	1,233	(849)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 6,371	6,371			6,371
Other comprehensive income (loss)	(93)	(93)				(93)
Issuance of common stock (in shares)			41
Issuance of common stock		312		312
Repurchase of common stock (in shares)			(220)
Repurchase of common stock		(10,042)		(2,049)	(7,993)
Shares repurchased for tax withholdings on vesting of restricted stock units (in shares)			(11)
Shares repurchased for tax withholdings on vesting of restricted stock units		(514)		(514)
Cash dividends declared		(2,970)			(2,970)
Share-based compensation		792		792
Ending balance (in shares) at Jan. 26, 2019			4,424
Ending balance at Jan. 26, 2019		40,789		41,361	538	(1,110)
Beginning balance (in shares) at Oct. 27, 2018			4,517
Beginning balance at Oct. 27, 2018		43,848		41,897	3,169	(1,218)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,822	2,822			2,822
Other comprehensive income (loss)	$ 108	108				108
Issuance of common stock (in shares)			22
Issuance of common stock		304		304
Repurchase of common stock (in shares)	(111)		(111)
Repurchase of common stock		(5,016)		(1,033)	(3,983)
Shares repurchased for tax withholdings on vesting of restricted stock units (in shares)			(4)
Shares repurchased for tax withholdings on vesting of restricted stock units		(196)		(196)
Cash dividends declared		(1,470)			(1,470)
Share-based compensation		389		389
Ending balance (in shares) at Jan. 26, 2019			4,424
Ending balance at Jan. 26, 2019		40,789		41,361	538	(1,110)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of adoption of accounting standards						(168)
Beginning balance (in shares) at Jul. 27, 2019			4,250
Beginning balance at Jul. 27, 2019		33,571		40,266	(5,903)	(792)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)	(16)
Ending balance (in shares) at Oct. 26, 2019			4,241
Ending balance at Oct. 26, 2019		34,423		40,321	(5,083)	(815)
Beginning balance (in shares) at Jul. 27, 2019			4,250
Beginning balance at Jul. 27, 2019		33,571		40,266	(5,903)	(792)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 5,804	5,804			5,804
Other comprehensive income (loss)	92	92				92
Issuance of common stock (in shares)			34
Issuance of common stock		334		334
Repurchase of common stock (in shares)			(34)
Repurchase of common stock		(1,638)		(325)	(1,313)
Shares repurchased for tax withholdings on vesting of restricted stock units (in shares)			(9)
Shares repurchased for tax withholdings on vesting of restricted stock units		(437)		(437)
Cash dividends declared		(2,972)			(2,972)
Share-based compensation		779		779
Ending balance (in shares) at Jan. 25, 2020			4,241
Ending balance at Jan. 25, 2020		35,533		40,617	(4,384)	(700)
Beginning balance (in shares) at Oct. 26, 2019			4,241
Beginning balance at Oct. 26, 2019		34,423		40,321	(5,083)	(815)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,878	2,878			2,878
Other comprehensive income (loss)	$ 115	115				115
Issuance of common stock (in shares)			23
Issuance of common stock		332		332
Repurchase of common stock (in shares)	(18)		(18)
Repurchase of common stock		(870)		(177)	(693)
Shares repurchased for tax withholdings on vesting of restricted stock units (in shares)			(5)
Shares repurchased for tax withholdings on vesting of restricted stock units		(243)		(243)
Cash dividends declared		(1,486)			(1,486)
Share-based compensation		384		384
Ending balance (in shares) at Jan. 25, 2020			4,241
Ending balance at Jan. 25, 2020		35,533		$ 40,617	(4,384)	(700)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of adoption of accounting standards		$ 3,729			$ 3,897	$ (168)