Business And Geographic Segment Information Business And Geographic Segment Information (Geographic Information, Net Sales) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jul. 28, 2019	Apr. 28, 2019	Jan. 27, 2019	Oct. 28, 2018	Jul. 29, 2018	Apr. 29, 2018	Jan. 28, 2018	Oct. 29, 2017	Jul. 28, 2019	Jul. 29, 2018	Jul. 30, 2017
Segment Reporting Information [Line Items]
Net sales	$ 1,780	$ 1,953	$ 2,172	$ 2,202	$ 1,745	$ 1,618	$ 1,614	$ 1,638	$ 8,107	$ 6,615	$ 5,837
UNITED STATES
Segment Reporting Information [Line Items]
Net sales									7,492	6,068	5,371
Other Countries [Member]
Segment Reporting Information [Line Items]
Net sales									$ 615	$ 547	$ 466