Financial Instruments (Derivatives Not Designated As Hedges) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Apr. 26, 2020	Jan. 26, 2020	Apr. 28, 2019	Apr. 26, 2020	Apr. 28, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	$ 35		$ 2	$ 26	$ 6
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	2	0
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	(1)		0	(1)	0
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	31		6	27	7
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	5		(4)	1	(1)
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)	$ 0