Employee Benefit Plans (Summary of Share-Based Awards available for Grant) (Details) - shares	9 Months Ended	12 Months Ended
	Apr. 28, 2018	Jul. 29, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Balance, beginning of period (in shares)	272,000,000	242,000,000
Restricted stock, stock units, and other share-based awards granted (in shares)	(50,000,000)	(76,000,000)
Share-based awards canceled/forfeited/expired (in shares)	14,000,000	78,000,000
Shares withheld for taxes and not issued (in shares)	20,000,000	28,000,000
Balance, end of period (in shares)	256,000,000	272,000,000