Employee Stock Plans (Narrative) (Details) (USD $)	3 Months Ended			9 Months Ended				12 Months Ended					9 Months Ended	12 Months Ended
	Apr. 30, 2011	Oct. 30, 2010	May 01, 2010	Apr. 30, 2011	May 01, 2010	Apr. 29, 2011	Jul. 31, 2010	Jul. 28, 2007 Supplemental Plan [Member]	Apr. 30, 2011 Employee Stock Purchase Rights [Member]	Nov. 12, 2009 Employee Stock Purchase Rights [Member]	Nov. 15, 2007 Employee Stock Purchase Rights [Member] Two Thousand Five Plan [Member]	Apr. 30, 2011 Employee Stock Purchase Rights [Member] Nineteen Ninety Six Plan [Member]	Apr. 30, 2011 Two Thousand Five Plan [Member]	Jul. 29, 2006 Nineteen Ninety Six Plan [Member]	Apr. 30, 2011 Nineteen Ninety Six Plan [Member]
Unrecognized compensation cost related to unvested share-based awards	$ 2,900,000,000			$ 2,900,000,000
Expected period of recognition of compensation cost, years				2.4
Income tax benefit for employee share-based compensation expense	$ 107,000,000		$ 118,000,000	$ 335,000,000	$ 304,000,000
Expiration date for stock options and stock appreciation rights, max time from grant date prior to date													9
Expiration date for stock options and stock appreciation rights, max time from grant date after date													10		9
Reduction in number of shares available for issuance prior										2.5
Expected dividend yield				0.00%
Reduction in number of shares available for issuance										1.5
Shares reserved for issuance								9,000,000
Closing stock price						$ 17.52
Shares for eligible employees, offering period (months)				24
Purchase period relating to stock discount (months)				6
Stock options and stock appreciation rights exercise price percentage of the fair market value of the underlying stock on the grant date													100.00%	100.00%
Percentage in which stock options become exercisable for within one year from the date of grant, minimum													20.00%	20.00%
Percentage in which stock options become exercisable for within one year from the date of grant, maximum													25.00%	25.00%
Number of months in which stock options ratably exercise, minimum													36	36
Number of months in which stock options ratably exercise, maximum													48	48
Ratable vesting period														60
Stock options exercisable	575,000,000			575,000,000			606,000,000
In-the-money exercisable stock option shares	69,000,000			69,000,000
Stock options exercisable, weighted-average exercise price per share	$ 21.18			$ 21.18			$ 20.51
Stock purchase plan - shares of the Company's common stock reserved for issuance									471,400,000
Consecutive six month periods				4
Percentage discount that employees may purchase a limited amount of stock, lesser of the market value		15.00%
Shares issued under employee purchase plan				17,000,000	14,000,000
Shares reserved in employee stock incentive plan									139,000,000		559,000,000	2,500,000,000
Termination of purchase plan				January 3, 2020