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 (loss)	(9)				(7)	(2)
Issuance of stock under employee stock plans, net of shares withheld for employee taxes (in shares)		1,224
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	44		44
Stock repurchases under stock repurchase programs (in shares)		(1,225)
Stock repurchases under stock repurchase programs	(170)			(170)
Dividends and dividend rights declared	(100)					(100)
Share-based compensation expense	98		98
Ending Balance (in shares) at Oct. 31, 2017		255,667
Ending Balance at Oct. 31, 2017	1,562		4,999	(10,948)	(29)	7,540
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 (loss)	30				(4)	34
Issuance of stock under employee stock plans, net of shares withheld for employee taxes (in shares)		1,422
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	$ 57		57
Stock repurchases under stock repurchase programs (in shares)	(467)	(467)
Stock repurchases under stock repurchase programs	$ (101)			(101)
Dividends and dividend rights declared	(126)					(126)
Share-based compensation expense	106		106
Ending Balance (in shares) at Oct. 31, 2018		259,571
Ending Balance at Oct. 31, 2018	$ 2,782		$ 5,501	$ (11,151)	$ (40)	$ 8,472