Fair Value (Fair Value On A Nonrecurring Basis) (Detail) (Fair Value, Measurements, Nonrecurring, Fair Value, Inputs, Level 3 [Member], Investments In Privately Held Companies, USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 26, 2013	Oct. 27, 2012
Gains or Losses Included In Other Income (Loss), Net
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Gains (Losses) for the Period	$ (1)	$ (10)
Net Carrying Value
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Investment in privately held companies	$ 0	$ 42