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	3 Months Ended		6 Months Ended
	Jan. 23, 2016	Jan. 24, 2015	Jan. 23, 2016	Jan. 24, 2015
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	$ (16)	$ 43	$ 111	$ 119
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	18	(43)	(107)	(122)
Equity derivatives | Other income (loss), net
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	0	(18)	0	(12)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	0	18	0	12
Interest rate derivatives | Interest expense
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	(16)	61	111	131
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	$ 18	$ (61)	$ (107)	$ (134)