Financial Instruments (Derivatives Not Designated As Hedges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2017	May 01, 2016	Apr. 30, 2017	May 01, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives Not Designated as Hedging Instruments	$ 3	$ 5	$ (6)	$ 4
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	0	(1)	(1)	0
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	(2)	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	21	0	9
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	3	(9)	(3)	0
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	$ 0	$ (4)	$ (2)	$ (4)