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Variable Interest Entity (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
Variable Interest Entity (Details) - USD ($) $ in Millions	May 08, 2020	Apr. 26, 2020	Apr. 26, 2020	Apr. 28, 2019	Jul. 28, 2019	Feb. 29, 2016
Other assets		$ 289	$ 289		$ 127
Investment (gains) / losses			49	$ 0
Other current assets		111	111		71
Variable Interest Entity, Primary Beneficiary [Member]
Other assets					$ 76
Other current assets		29	$ 29
Acre Venture Partners [Member]
LLC ownership percentage			99.80%
Investments funded		86	$ 86
Investment (gains) / losses		$ 45
Acre Venture Partners [Member] \| Subsequent Event [Member]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries	$ 30
Acre Venture Partners [Member] \| Total Commitment [Member]
Other Commitment						$ 125