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, shares at Jul. 31, 2015		277,706
Beginning Balance at Jul. 31, 2015	$ 2,332		$ 4,010	$ (7,675)	$ (30)	$ 6,027
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(19)				(12)	(7)
Issuance of stock under employee stock plans, net of shares withheld for employee taxes, shares		1,901
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	$ 56		56
Stock repurchases under stock repurchase programs, shares	(19,100)	(19,134)
Stock repurchases under stock repurchase programs	$ (1,725)			(1,725)
Dividends and dividend rights declared	(163)					(163)
Tax benefit from share-based compensation plans	20		20
Share-based compensation expense	140		140
Ending Balance, shares at Jan. 31, 2016		260,473
Ending Balance at Jan. 31, 2016	641		4,226	(9,400)	(42)	5,857
Beginning Balance, shares at Jul. 31, 2016		257,853
Beginning Balance at Jul. 31, 2016	1,161		4,445	(9,939)	(32)	6,687
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(19)				(2)	(17)
Issuance of stock under employee stock plans, net of shares withheld for employee taxes, shares		1,649
Issuance of stock under employee stock plans, net of shares withheld for employee taxes	$ 35		35
Stock repurchases under stock repurchase programs, shares	(3,500)	(3,500)
Stock repurchases under stock repurchase programs	$ (390)			(390)
Dividends and dividend rights declared	(178)					(178)
Share-based compensation expense	174		174
Ending Balance, shares at Jan. 31, 2017		256,002
Ending Balance at Jan. 31, 2017	785		4,660	$ (10,329)	$ (34)	6,488
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle	$ 2		$ 6			$ (4)