Financial Instruments (Derivatives Not Designated As Hedges) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 28, 2019	Jul. 29, 2018	Jul. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	$ 3	$ (24)	$ 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	0	(1)	1
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	(1)	14
Foreign Exchange Forward Contracts [Member] | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	0	0	(1)
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	6	(2)	(11)
Commodity Derivative Contracts [Member] | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	(1)	0	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	(2)	(2)	(3)
Treasury Lock [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) or Loss Recognized in Earnings on Derivatives	$ 0	$ (18)	$ 0