Employee Benefit Plans (Summary of Share-Based Awards available for Grant) (Details) - shares	6 Months Ended	12 Months Ended
	Jan. 26, 2019	Jul. 28, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Balance, beginning of period (in shares)	245,000,000	272,000,000
Restricted stock, stock units, and other share-based awards granted (in shares)	(37,000,000)	(70,000,000)
Share-based awards canceled/forfeited/expired (in shares)	12,000,000	18,000,000
Shares withheld for taxes and not issued (in shares)	15,000,000	25,000,000
Other (in shares)	1,000,000
Balance, end of period (in shares)	236,000,000	245,000,000