Derivative Instruments (Effect Of Derivative Instruments Designated As Cash Flow Hedges On Other Comprehensive Income And Consolidated Statements Of Operations Summary) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 29, 2017	Apr. 30, 2016	Apr. 29, 2017	Apr. 30, 2016
Derivatives designated as cash flow hedging instruments:
Derivative [Line Items]
GAINS (LOSSES) RECOGNIZED IN OCI ON DERIVATIVES FOR THE THREE MONTHS ENDED (EFFECTIVE PORTION)	$ 25	$ 21	$ (23)	$ (3)
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME FOR THE THREE MONTHS ENDED (EFFECTIVE PORTION)	(27)	(9)	(66)	(17)
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
GAINS (LOSSES) RECOGNIZED IN OCI ON DERIVATIVES FOR THE THREE MONTHS ENDED (EFFECTIVE PORTION)	25	21	(23)	(3)
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives | Operating expenses
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME FOR THE THREE MONTHS ENDED (EFFECTIVE PORTION)	(20)	(7)	(50)	(13)
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives | Cost of sales—service
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME FOR THE THREE MONTHS ENDED (EFFECTIVE PORTION)	(7)	(2)	(16)	(4)
Derivatives designated as net investment hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
GAINS (LOSSES) RECOGNIZED IN OCI ON DERIVATIVES FOR THE THREE MONTHS ENDED (EFFECTIVE PORTION)	(10)	(15)	(4)	(4)
Derivatives designated as net investment hedging instruments: | Foreign currency derivatives | Other income (loss), net
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME FOR THE THREE MONTHS ENDED (EFFECTIVE PORTION)	$ 0	$ 0	$ 0	$ 0