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		6 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018
Derivatives designated as cash flow hedging instruments:
Derivative [Line Items]
GAINS (LOSSES) RECOGNIZED IN OCI ON DERIVATIVES (EFFECTIVE PORTION)	$ (6)	$ 30	$ (10)	$ 38
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME (EFFECTIVE PORTION)	1	18	1	31
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
GAINS (LOSSES) RECOGNIZED IN OCI ON DERIVATIVES (EFFECTIVE PORTION)	(6)	30	(10)	38
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives | Revenue | Product
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME (EFFECTIVE PORTION)	1	0	1	0
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives | Revenue | Service
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME (EFFECTIVE PORTION)	1	0	2	0
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives | Cost of sales | Service
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME (EFFECTIVE PORTION)	(1)	4	(1)	7
Derivatives designated as cash flow hedging instruments: | Foreign currency derivatives | Operating expenses
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME (EFFECTIVE PORTION)	0	14	(1)	24
Derivatives designated as net investment hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
GAINS (LOSSES) RECOGNIZED IN OCI ON DERIVATIVES (EFFECTIVE PORTION)	(1)	(12)	3	(17)
Derivatives designated as net investment hedging instruments: | Foreign currency derivatives | Other income (loss), net
Derivative [Line Items]
GAINS (LOSSES) RECLASSIFIED FROM AOCI INTO INCOME (EFFECTIVE PORTION)	$ 0	$ 0	$ 0	$ 0