Financial Instruments (Derivatives Not Designated As Hedges) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 29, 2017	Jan. 31, 2016	Jan. 29, 2017	Jan. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives Not Designated as Hedging Instruments	$ (7)	$ (3)	$ (9)	$ (1)
Foreign Exchange Contract [Member] | Cost Of Products Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives Not Designated as Hedging Instruments	(1)	1	(1)	1
Foreign Exchange Contract [Member] | Other Expenses/Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives Not Designated as Hedging Instruments	0	1	0	1
Currency Swap [Member] | Other Expenses/Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives Not Designated as Hedging Instruments	0	(12)	0	(12)
Commodity Derivative Contracts [Member] | Cost Of Products Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives Not Designated as Hedging Instruments	(2)	7	(6)	9
Deferred Compensation Derivative Contracts [Member] | General and Administrative Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives Not Designated as Hedging Instruments	$ (4)	$ 0	$ (2)	$ 0