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. 29, 2018	Apr. 29, 2018	Jan. 28, 2018	Oct. 29, 2017	Jul. 30, 2017	Apr. 30, 2017	Jan. 29, 2017	Oct. 30, 2016	Jul. 29, 2018	Jul. 30, 2017	Jul. 31, 2016
Segment Reporting Information [Line Items]
Net sales	$ 2,219	$ 2,125	$ 2,180	$ 2,161	$ 1,664	$ 1,853	$ 2,171	$ 2,202	$ 8,685	$ 7,890	$ 7,961
UNITED STATES
Segment Reporting Information [Line Items]
Net sales									7,032	6,357	6,437
AUSTRALIA
Segment Reporting Information [Line Items]
Net sales									622	610	590
Other Countries [Member]
Segment Reporting Information [Line Items]
Net sales									$ 1,031	$ 923	$ 934