Pension And Postretirement Benefits (Amounts Recognized in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Jul. 28, 2019	Jul. 29, 2018
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	$ 21	$ 61
Noncurrent liabilities of discontinued operations	65	64
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	21	61
Liability, Defined Benefit Plan, Current	14	14
Liability, Defined Benefit Plan, Noncurrent	179	141
Noncurrent liabilities of discontinued operations	20	9
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	192	103
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax	1	2
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	0	0
Liability, Defined Benefit Plan, Current	25	29
Liability, Defined Benefit Plan, Noncurrent	210	206
Noncurrent liabilities of discontinued operations	0	0
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	235	235
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax	$ (38)	$ (67)