Stockholders' Equity (Details) (USD $)	3 Months Ended
	Oct. 31, 2011		Oct. 31, 2010	Nov. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pool Shares Reduced For Each Share Granted	2.3
Pool Shares Increased For Each Share Forfeited	2.3
Stockholders' Equity (Textuals)
Common stock repurchased, share	5,200,000		7,300,000
Common stock repurchased, value	$ 255,000,000		$ 330,000,000
Common Stock, Dividends, Per Share, Cash Paid	$ 0.15
Payments of Dividends	45,000,000		0
Dividends Payable, Amount Per Share				$ 0.15
Total share-based compensation expense
Share-based compensation expense	40,000,000		35,000,000
Income tax benefit	(13,000,000)		(12,000,000)
Increase in net loss	27,000,000		23,000,000
Increase in net loss per share:
Basic	$ 0.09		$ 0.07
Diluted	$ 0.09		$ 0.07
Activity under all share-based compensation plans [Roll Forward]
Shares available for grant, Beginning Balance	30,716,000
Number of shares, Balance at July 31, 2010	22,679,000
Weighted average exercise price per share, Balance at July 31, 2011	$ 32.38
Options granted, shares available for grant	(157,000)
Options granted, number of shares	157,000
Options granted, weighted average exercise price per share	$ 45.32
Restricted stock units granted, shares available for grant	648,000	[1]
Options exercised, number of shares	(1,882,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 27.49
Options exercised, weighted average exercise price per share	$ 27.49
Options canceled or expired, shares available for grant	197,000	[2]
Options canceled or expired, number of shares	(199,000)	[2]
Options canceled or expired, weighted average exercise price per share	$ 35.98	[2]
Restricted stock units forfeited, shares available for grant	590,000	[1],[2]
Shares available for grant, Ending Balance	30,698,000
Number of shares, Balance at October 31, 2011	20,755,000
Weighted average exercise price per share, Balance at October 31, 2011	$ 32.89
Exercisable at October 31, 2011	13,190,000
Weighted average exercise price per share, Exercisable at October 31, 2011	$ 29.17
Summary of restricted stock unit activity
Nonvested at July 31, 2011	11,055,000
Nonvested, Weighted Average Grant Date Fair Value, at July 31, 2011	$ 37.92
Granted, Number of shares	220,000
Granted, Weighted Average Grant Date Fair Value	$ 43.34
Vested, Number of Shares	(1,415,000)
Vested, Weighted Average Grant Date Fair Value	$ 32.77
Forfeited, Number of Shares	(241,000)
Forfeited, Weighted Average Grant Date Fair Value	$ 36.35
Nonvested at October 31, 2011	9,619,000
Nonvested, Weighted Average Grant Date Fair Value, at October 31, 2011	$ 38.84
Stock Options And Restricted Stock [Member]
Stockholders' Equity (Textuals)
Unrecognized compensation cost related to non-vested share based compensation expense	60,000,000
Expected weighted average vesting period to recognize compensation cost related to share based compensation expense, in years	1.99
Restricted Stock Units (RSUs) [Member]
Stockholders' Equity (Textuals)
Unrecognized compensation cost related to non-vested share based compensation expense	208,000,000
Expected weighted average vesting period to recognize compensation cost related to share based compensation expense, in years	2.31
Cost of Sales [Member]
Total share-based compensation expense
Share-based compensation expense	1,000,000		1,000,000
Selling and Marketing Expense [Member]
Total share-based compensation expense
Share-based compensation expense	14,000,000		9,000,000
Research and Development Expense [Member]
Total share-based compensation expense
Share-based compensation expense	12,000,000		13,000,000
General and Administrative Expense [Member]
Total share-based compensation expense
Share-based compensation expense	13,000,000		12,000,000
Current Program [Member]
Stockholders' Equity (Textuals)
Stock Repurchase Program, Remaining Authorized Repurchase Amount	385,000,000
New Program [Member]
Stockholders' Equity (Textuals)
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 2,000,000,000

[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.