Stockholders' Equity (Details) (USD $)	3 Months Ended			6 Months Ended
	Jan. 31, 2012	Oct. 31, 2011	Jan. 31, 2011	Jan. 31, 2012		Jan. 31, 2011	Feb. 29, 2012
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				11,400,000		18,500,000
Common stock repurchased, value				$ (586,000,000)		$ (860,000,000)
Common Stock, Dividends, Per Share, Cash Paid	$ 0.15
Payments of Dividends	44,000,000	45,000,000	0	89,000,000		0
Dividends Payable, Amount Per Share							$ 0.15
Total share-based compensation expense
Share-based compensation expense	43,000,000		38,000,000	83,000,000		73,000,000
Income tax benefit	(14,000,000)		(13,000,000)	(27,000,000)		(25,000,000)
Decrease in net income	29,000,000		25,000,000	56,000,000		48,000,000
Decrease in net income per share:
Basic	$ 0.1		$ 0.08	$ 0.19		$ 0.15
Diluted	$ 0.09		$ 0.08	$ 0.18		$ 0.15
Activity under all share-based compensation plans [Roll Forward]
Shares available for grant, Beginning Balance		30,716,000		30,716,000
Number of shares, Balance at July 31, 2011		22,679,000		22,679,000
Weighted average exercise price per share, Balance at July 31, 2011		$ 32.38		$ 32.38
Options granted, shares available for grant				(238,000)
Options granted, number of shares				238,000
Options granted, weighted average exercise price per share	$ 48.09			$ 48.09
Restricted stock units granted, shares available for grant				(965,000)	[1]
Options exercised, number of shares				(4,051,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 28.19			$ 28.19
Options exercised, weighted average exercise price per share	$ 28.19			$ 28.19
Options canceled or expired, shares available for grant				264,000	[2]
Options canceled or expired, number of shares				(267,000)	[2]
Options canceled or expired, weighted average exercise price per share				$ 36.45	[2]
Restricted stock units forfeited, shares available for grant				868,000	[1],[2]
Shares available for grant, Ending Balance	30,645,000			30,645,000
Number of shares, Balance at January 31, 2012	18,599,000			18,599,000
Weighted average exercise price per share, Balance at January 31, 2012	$ 33.44			$ 33.44
Exercisable at January 31, 2012	11,956,000			11,956,000
Weighted average exercise price per share, Exercisable at January 31, 2012	$ 29.64			$ 29.64
Summary of restricted stock unit activity
Nonvested at July 31, 2011		11,055,000		11,055,000
Nonvested, Weighted Average Grant Date Fair Value, at July 31, 2011		$ 37.92		$ 37.92
Granted, Number of shares				419,000
Granted, Weighted Average Grant Date Fair Value				$ 46.57
Vested, Number of Shares				(1,678,000)
Vested, Weighted Average Grant Date Fair Value				$ 32.79
Forfeited, Number of Shares				(377,000)
Forfeited, Weighted Average Grant Date Fair Value	$ 37.42			$ 37.42
Nonvested at January 31, 2012	9,419,000			9,419,000
Nonvested, Weighted Average Grant Date Fair Value, at January 31, 2012	$ 39.24			$ 39.24
Stock Options And Restricted Stock [Member]
Stockholders' Equity (Textuals)
Unrecognized compensation cost related to non-vested share based compensation expense	51,000,000			51,000,000
Expected weighted average vesting period to recognize compensation cost related to share based compensation expense, in years				1.84
Restricted Stock Units (RSUs) [Member]
Stockholders' Equity (Textuals)
Unrecognized compensation cost related to non-vested share based compensation expense	188,000,000			188,000,000
Expected weighted average vesting period to recognize compensation cost related to share based compensation expense, in years				2.14
Cost of Sales [Member]
Total share-based compensation expense
Share-based compensation expense	2,000,000		2,000,000	3,000,000		3,000,000
Selling and Marketing Expense [Member]
Total share-based compensation expense
Share-based compensation expense	15,000,000		12,000,000	29,000,000		21,000,000
Research and Development Expense [Member]
Total share-based compensation expense
Share-based compensation expense	14,000,000		12,000,000	26,000,000		25,000,000
General and Administrative Expense [Member]
Total share-based compensation expense
Share-based compensation expense	12,000,000		12,000,000	25,000,000		24,000,000
Current Program [Member]
Stockholders' Equity (Textuals)
Stock Repurchase Program, Remaining Authorized Repurchase Amount				53,000,000
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.