Financial Instruments (Derivatives Not Designated As Hedges) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 26, 2020	Jan. 31, 2021	Jan. 26, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	$ (16)	$ (6)	$ (17)	$ (9)
Foreign Exchange Forward Contracts [Member] | Cost Of Products Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	0	0	1	0
Foreign Exchange Forward Contracts [Member] | Other Expenses/Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	0	0	0	2
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	(13)	0	(15)	(4)
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	(3)	(3)	(3)	(4)
Treasury Lock [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	$ 0	$ (3)	$ 0	$ (3)