Restructuring Charges (Schedule Of Restructuring Activity And Related Reserves) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jan. 27, 2013
2013 Initiatives [Member]
Restructuring Reserve [Roll Forward]
Restructuring and Related Cost, Incurred Cost	$ 85
Accrued Balance at end of period	22
2013 Initiatives [Member] | Severance Pay And Benefits [Member]
Restructuring Reserve [Roll Forward]
Restructuring and Related Cost, Incurred Cost	22
Accrued Balance at end of period	22
2013 Initiatives [Member] | Restructuring Charges Subtotal [Member]
Restructuring Reserve [Roll Forward]
Restructuring and Related Cost, Incurred Cost	22
2013 Initiatives [Member] | Asset Impairment Accelerated Depreciation [Member]
Restructuring Reserve [Roll Forward]
Restructuring and Related Cost, Incurred Cost	61
2013 Initiatives [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Restructuring and Related Cost, Incurred Cost	2
2011 Initiatives [Member]
Restructuring Reserve [Roll Forward]
Accrued Balance at beginning of period	16
Cash Payments	(8)
Accrued Balance at end of period	8
2011 Initiatives [Member] | Severance Pay And Benefits [Member]
Restructuring Reserve [Roll Forward]
Accrued Balance at beginning of period	14
Cash Payments	(8)
Accrued Balance at end of period	6
2011 Initiatives [Member] | Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Accrued Balance at beginning of period	2
Cash Payments
Accrued Balance at end of period	$ 2