Derivative Instruments (Derivatives Recorded At Fair Value) (Details) - USD ($) $ in Millions	Jan. 28, 2017	Jul. 30, 2016
Derivative [Line Items]
DERIVATIVE ASSETS	$ 118	$ 385
DERIVATIVE LIABILITIES	59	54
Derivatives designated as hedging instruments:
Derivative [Line Items]
DERIVATIVE ASSETS	116	384
DERIVATIVE LIABILITIES	58	53
Derivatives designated as hedging instruments: | Foreign currency derivatives | Other current assets
Derivative [Line Items]
DERIVATIVE ASSETS	5	7
Derivatives designated as hedging instruments: | Foreign currency derivatives | Other current liabilities
Derivative [Line Items]
DERIVATIVE LIABILITIES	58	53
Derivatives designated as hedging instruments: | Interest rate derivatives | Other current assets
Derivative [Line Items]
DERIVATIVE ASSETS	2	11
Derivatives designated as hedging instruments: | Interest rate derivatives | Other current liabilities
Derivative [Line Items]
DERIVATIVE LIABILITIES	0	0
Derivatives designated as hedging instruments: | Interest rate derivatives | Other assets
Derivative [Line Items]
DERIVATIVE ASSETS	109	366
Derivatives designated as hedging instruments: | Interest rate derivatives | Other long-term liabilities
Derivative [Line Items]
DERIVATIVE LIABILITIES	0	0
Derivatives not designated as hedging instruments:
Derivative [Line Items]
DERIVATIVE ASSETS	2	1
DERIVATIVE LIABILITIES	1	1
Derivatives not designated as hedging instruments: | Foreign currency derivatives | Other current assets
Derivative [Line Items]
DERIVATIVE ASSETS	2	0
Derivatives not designated as hedging instruments: | Foreign currency derivatives | Other current liabilities
Derivative [Line Items]
DERIVATIVE LIABILITIES	1	1
Derivatives not designated as hedging instruments: | Equity derivatives/warrants | Other assets
Derivative [Line Items]
DERIVATIVE ASSETS	0	1
Derivatives not designated as hedging instruments: | Equity derivatives/warrants | Other long-term liabilities
Derivative [Line Items]
DERIVATIVE LIABILITIES	$ 0	$ 0