Supplemental Financial Statement Data (Schedule of Statements of Cash Flow) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 29, 2018	Jul. 30, 2017	Jul. 31, 2016
Statement of Financial Position [Abstract]
Employee Benefits And Deferred Compensation Payments	$ (59)	$ (58)	$ (57)
Other Operating Activities, Cash Flow Statement	(1)	0	(3)
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities	(60)	(58)	(60)
Interest Paid	152	110	113
Interest Received	4	5	4
Income Taxes Paid, Net	$ 128	$ 320	$ 325