Fair Value (Fair Value On A Nonrecurring Basis) (Detail) (USD $) In Millions, unless otherwise specified					3 Months Ended
	Oct. 27, 2012	Jul. 28, 2012	Oct. 27, 2012 Fair Value, Measurements, Nonrecurring [Member] Net Carrying Value [Member] Fair Value, Inputs, Level 3 [Member]	Oct. 29, 2011 Fair Value, Measurements, Nonrecurring [Member] Net Carrying Value [Member] Fair Value, Inputs, Level 3 [Member]	Oct. 27, 2012 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Investments In Privately Held Companies [Member]	Oct. 29, 2011 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Investments In Privately Held Companies [Member]	Oct. 29, 2011 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Property Held For Sale [Member]	Oct. 27, 2012 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Oct. 29, 2011 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in privately held companies	$ 239	$ 249	$ 42	$ 1
Property Held For Sale Fair Value Disclosure				24
Fair Value Nonrecurring Basis Gain Loss Recorded Total					$ (10)	$ (1)	$ (89)	$ (10)	$ (90)