Goodwill And Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Millions	6 Months Ended
	Jan. 26, 2020	Jul. 28, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 865	$ 869
Finite-Lived Intangible Assets, Accumulated Amortization	(103)	(83)
Finite-Lived Intangible Assets, Net	762	786
Indefinite-lived Intangible Assets (Excluding Goodwill)	2,611	2,629
Total net intangible assets	3,373	3,415
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	851	855
Finite-Lived Intangible Assets, Accumulated Amortization	(89)	(70)
Finite-Lived Intangible Assets, Net	$ 762	785
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	22 years
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 14	14
Finite-Lived Intangible Assets, Accumulated Amortization	(14)	(13)
Finite-Lived Intangible Assets, Net	$ 0	$ 1
Other Intangible Assets [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year 6 months
Other Intangible Assets [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years