Financial Instruments (Derivatives Not Designated As Hedges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 29, 2018	Apr. 30, 2017	Apr. 29, 2018	Apr. 30, 2017
Derivative Instruments, Gain Loss [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, (Gain) Loss, Net	$ (16)	$ 3	$ (23)	$ (6)
Foreign Exchange Forward Contracts [Member] | Cost Of Products Sold [Member]
Derivative Instruments, Gain Loss [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, (Gain) Loss, Net	0	0	0	(1)
Foreign Exchange Forward Contracts [Member] | Other Expenses/Income [Member]
Derivative Instruments, Gain Loss [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, (Gain) Loss, Net	0	0	(1)	0
Commodity Derivative Contracts [Member] | Cost Of Products Sold [Member]
Derivative Instruments, Gain Loss [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, (Gain) Loss, Net	(3)	3	(3)	(3)
Deferred Compensation Derivative Contracts [Member] | Administrative expenses [Member]
Derivative Instruments, Gain Loss [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, (Gain) Loss, Net	4	0	(1)	(2)
Treasury Lock [Member] | Interest Expense [Member]
Derivative Instruments, Gain Loss [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, (Gain) Loss, Net	$ (17)	$ 0	$ (18)	$ 0