Employee Benefit Plans (Summary of Share-Based Awards available for Grant) (Details) - shares	9 Months Ended	12 Months Ended
	Apr. 29, 2017	Jul. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Balance, beginning of period (in shares)	242,000,000	276,000,000
Restricted stock, stock units, and other share-based awards granted (in shares)	(45,000,000)	(96,000,000)
Share-based awards canceled/forfeited/expired (in shares)	74,000,000	30,000,000
Shares withheld for taxes and not issued (in shares)	23,000,000	30,000,000
Other (in shares)		2,000,000
Balance, end of period (in shares)	294,000,000	242,000,000