Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Millions	Total	Shares of Common Stock	Common Stock and Additional Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Loss	Retained Earnings
Beginning Balance (in shares) at Jul. 31, 2017		255,668
Beginning Balance at Jul. 31, 2017	$ 1,699		$ 4,857	$ (10,778)	$ (22)	$ 7,642
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	1,357				(10)	1,367
Issuance of stock under employee stock plans, net of shares withheld for employee taxes (in shares)		2,776
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	147		147
Stock repurchases under stock repurchase programs (in shares)		(1,870)
Stock repurchases under stock repurchase programs	(272)			(272)
Dividends and dividend rights declared	(304)					(304)
Share-based compensation expense	285		285
Ending Balance (in shares) at Apr. 30, 2018		256,574
Ending Balance at Apr. 30, 2018	2,912		5,289	(11,050)	(32)	8,705
Beginning Balance (in shares) at Jan. 31, 2018		256,076
Beginning Balance at Jan. 31, 2018	1,721		5,151	(11,031)	(20)	7,621
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	1,174				(12)	1,186
Issuance of stock under employee stock plans, net of shares withheld for employee taxes (in shares)		613
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	46		46
Stock repurchases under stock repurchase programs (in shares)		(115)
Stock repurchases under stock repurchase programs	(19)			(19)
Dividends and dividend rights declared	(102)					(102)
Share-based compensation expense	92		92
Ending Balance (in shares) at Apr. 30, 2018		256,574
Ending Balance at Apr. 30, 2018	2,912		5,289	(11,050)	(32)	8,705
Beginning Balance (in shares) at Jul. 31, 2018		258,616
Beginning Balance at Jul. 31, 2018	2,816		5,338	(11,050)	(36)	8,564
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	1,599				(2)	1,601
Issuance of stock under employee stock plans, net of shares withheld for employee taxes (in shares)		2,603
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	$ 138		138
Stock repurchases under stock repurchase programs (in shares)	(1,900)	(1,885)
Stock repurchases under stock repurchase programs	$ (413)			(413)
Dividends and dividend rights declared	(376)					(376)
Share-based compensation expense	306		306
Ending Balance (in shares) at Apr. 30, 2019		259,334
Ending Balance at Apr. 30, 2019	4,070		5,782	(11,463)	(38)	9,789
Beginning Balance (in shares) at Jan. 31, 2019		259,110
Beginning Balance at Jan. 31, 2019	2,796		5,623	(11,328)	(36)	8,537
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	1,376				(2)	1,378
Issuance of stock under employee stock plans, net of shares withheld for employee taxes (in shares)		767
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	60		60
Stock repurchases under stock repurchase programs (in shares)		(543)
Stock repurchases under stock repurchase programs	(135)			(135)
Dividends and dividend rights declared	(126)					(126)
Share-based compensation expense	99		99
Ending Balance (in shares) at Apr. 30, 2019		259,334
Ending Balance at Apr. 30, 2019	$ 4,070		$ 5,782	$ (11,463)	$ (38)	$ 9,789