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		9 Months Ended
	Apr. 25, 2015	Apr. 26, 2014	Apr. 25, 2015	Apr. 26, 2014
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	$ (17)	$ 0	$ 102	$ (82)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	17	0	(105)	81
Equity derivatives | Other income (loss), net
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	(8)	(8)	(20)	(55)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	8	8	20	55
Interest rate derivatives | Interest expense
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	(9)	8	122	(27)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	$ 9	$ (8)	$ (125)	$ 26