Fair Value (Fair Value On A Nonrecurring Basis) (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 28, 2012	Apr. 30, 2011	Apr. 28, 2012	Apr. 30, 2011
Net Carrying Value [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Investments in privately held companies	$ 17	$ 11	$ 17	$ 11
Property held for sale	52		52
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Investments in privately held companies	17	11	17	11
Property held for sale	52		52
Recognized Gain (Loss) for the Period [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Recognized (gain) loss for period	(91)	(10)	(195)	(170)
Investments In Privately Held Companies [Member] | Recognized Gain (Loss) for the Period [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Recognized (gain) loss for period	(15)	(1)	(17)	(6)
Purchased Intangible Assets [Member] | Recognized Gain (Loss) for the Period [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Recognized (gain) loss for period		(9)		(164)
Property Held For Sale [Member] | Recognized Gain (Loss) for the Period [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Recognized (gain) loss for period	(76)		(192)
Gains On Assets No Longer Held [Member] | Recognized Gain (Loss) for the Period [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Recognized (gain) loss for period			$ 14