Stockholders' Equity (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		1 Months Ended		9 Months Ended
	Apr. 30, 2011	Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2011		Apr. 30, 2010	Apr. 30, 2011 Share Based Compensation Expense [Member]	Apr. 30, 2010 Share Based Compensation Expense [Member]	Apr. 30, 2011 Share Based Compensation Expense [Member]	Apr. 30, 2010 Share Based Compensation Expense [Member]	Feb. 28, 2011 Stock Options [Member]	Jan. 31, 2011 Stock Options [Member]	Apr. 30, 2011 Stock Options [Member]	Apr. 30, 2011 Restricted Stock [Member]
Total share-based compensation expense
Cost of product revenue		$ 32	$ 34	$ 110		$ 117	$ 2	$ 2	$ 5	$ 7
Selling and marketing		351	309	901		766	12	11	33	30
Research and development		164	141	478		426	13	10	38	30
General and administrative		93	102	271		267	12	11	36	31
Discontinued operations										1
Total share-based compensation expense		39	34	112		99	39	34	112	99
Income tax benefit		364	302	352		306	(14)	(12)	(39)	(35)
Decrease in net income							25	22	73	64
Decrease in net income per share:
Basic							$ 0.08	$ 0.07	$ 0.24	$ 0.2
Diluted							$ 0.08	$ 0.07	$ 0.23	$ 0.2
Stockholders' Equity (Textuals)
Common stock repurchased, share	700	4,900		23,300		24,600					4,200
Common stock repurchased, value				1,110		750						250
Additional stock available for repurchase	890	890		890
Accelerated Share Repurchases, Initial Price Paid Per Share		$ 51.12
Authorization from Board of Directors for additional stock repurchase, due date				Aug. 16, 2013
Unrecognized compensation cost related to non-vested share based compensation expense													$ 62	$ 142
Expected weighted average vesting period to recognize compensation cost related to share based compensation expense, in years													1.9	2.0
Terms of 2005 equity incentive plan as amended				Under the terms of our 2005 Equity Incentive Plan as amended on January 19, 2011, RSUs granted from the pool of shares available for grant on or after November 1, 2010 reduce the pool by 2.3 shares for each share granted. RSUs forfeited and returned to the pool of shares available for grant increase the pool by 2.3 shares for each share forfeited.
Activity under all share-based compensation plans
Shares available for grant, Beginning Balance				8,761
Number of shares, Balance at July 31, 2010				32,593
Weighted average exercise price per share, Balance at July 31, 2010				$ 28.45
Additional shares authorized, shares available for grant	31,000	31,000		31,000
Options granted, shares available for grant				(772)
Options granted, number of shares				772
Options granted, weighted average exercise price per share	$ 47.22	$ 47.22		$ 47.22
Restricted stock units granted, shares available for grant				(982)	[1]
Options exercised, number of shares				(10,361)
Options exercised, weighted average exercise price per share	$ 25.68	$ 25.68		$ 25.68
Options canceled or expired, shares available for grant				749	[2]
Options canceled or expired, number of shares				(787)	[2]
Options canceled or expired, weighted average exercise price per share				$ 31.08	[2]
Restricted stock units forfeited, shares available for grant				1,217	[1],[2]
Shares available for grant, Ending Balance	39,973	39,973		39,973
Number of shares, Balance at April 30, 2011	22,217	22,217		22,217
Weighted average exercise price per share, Balance at April 30, 2011	$ 30.3	$ 30.3		$ 30.3
Exercisable at April 30, 2011	13,342	13,342		13,342
Weighted average exercise price per share, Exercisable at April 30, 2011	$ 27.36	$ 27.36		$ 27.36
Summary of restricted stock unit activity
Nonvested, Number of shares, Beginning of period at July 31, 2010				11,531
Nonvested, Weighted Average Grant Date Fair Value, Beginning of period at July 31, 2010				$ 30.93
Granted, Number of shares				585
Granted, Weighted Average Grant Date Fair Value				$ 42.34
Vested, Number of Shares				(3,379)
Vested, Weighted Average Grant Date Fair Value				$ 26.21
Forfeited, Number of Shares				(692)
Forfeited, Weighted Average Grant Date Fair Value	$ 31.23	$ 31.23		$ 31.23
Nonvested, Number of shares, End of period at April 30, 2011	8,045	8,045		8,045
Nonvested, Weighted Average Grant Date Fair Value, End of period at April 30, 2011	$ 33.71	$ 33.71		$ 33.71

[1] Under the terms of our 2005 Equity Incentive Plan as amended on January 19, 2011, RSUs granted from the pool of shares available for grant on or after November 1, 2010 reduce the pool by 2.3 shares for each share granted. RSUs forfeited and returned to the pool of shares available for grant increase the pool by 2.3 shares for each share forfeited.

[2] Stock options and restricted stock units canceled, expired or forfeited under our 2005 Equity Incentive Plan are returned to the pool of shares available for grant. Stock options and restricted stock units canceled, expired or forfeited under older expired plans are not returned to the pool of shares available for grant.