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. 27, 2018	Jan. 28, 2017	Jan. 27, 2018	Jan. 28, 2017
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	$ (98)	$ (175)	$ (158)	$ (266)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	98	172	158	262
Interest rate derivatives | Interest expense
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	(63)	(175)	(109)	(266)
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	63	172	109	262
Equity derivatives | Other income (loss), net
Hedge Underlying Gain Loss [Line Items]
GAINS (LOSSES) ON DERIVATIVE INSTRUMENTS FOR THE THREE MONTHS ENDED	(35)	0	(49)	0
GAINS (LOSSES) RELATED TO HEDGED ITEMS FOR THE THREE MONTHS ENDED	$ 35	$ 0	$ 49	$ 0