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 - Interest rate derivatives - Interest expense - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 29, 2017	Apr. 30, 2016	Apr. 29, 2017	Apr. 30, 2016
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	$ (6)	$ 19	$ (272)	$ 130
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	$ 7	$ (18)	$ 269	$ (125)