Derivative Instruments (Effect Of Derivative Instruments Designated As Fair Value Hedges And Underlying Hedged Items On Consolidated Statements Of Operations) (Details) (Derivatives Designated as Fair Value Hedging Instruments, USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 25, 2014	Oct. 26, 2013
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	$ 76	$ (17)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	(79)	15
Equity derivatives | Other income (loss), net
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	6	(35)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	(6)	35
Interest rate derivatives | Interest expense
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	70	18
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	$ (73)	$ (20)