Restructuring And Other Charges (Schedule Of Activities Related To Restructuring And Other Charges) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Apr. 27, 2013	Jul. 28, 2012	Jul. 30, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring Gross Charges, Period Expense	$ 105	$ 353	$ 799
Change In Estimate Of Restructuring Reserves		(49)
Cash Payments	(174)	(436)	(449)
Non-Cash Items	(3)	(20)	(88)
Restructuring Reserve	38	110	262
Voluntary Early Retirement Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Gross Charges, Period Expense	0	0	453
Change In Estimate Of Restructuring Reserves		0
Cash Payments	0	(17)	(436)
Non-Cash Items	0	0	0
Restructuring Reserve	0	0	17
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Gross Charges, Period Expense	111	299	247
Change In Estimate Of Restructuring Reserves		(49)
Cash Payments	(164)	(401)	(13)
Non-Cash Items	0	0	0
Restructuring Reserve	30	83	234
Goodwill And Intangible Assets [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Gross Charges, Period Expense	0	0	71
Change In Estimate Of Restructuring Reserves		0
Cash Payments	0	0	0
Non-Cash Items	0	0	(71)
Restructuring Reserve	0	0	0
Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Gross Charges, Period Expense	(6)	54	28
Change In Estimate Of Restructuring Reserves		0
Cash Payments	(10)	(18)	0
Non-Cash Items	(3)	(20)	(17)
Restructuring Reserve	$ 8	$ 27	$ 11