Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions		6 Months Ended
	Jan. 26, 2018	Jan. 31, 2018	Jan. 31, 2017
Stockholders' Equity Note [Abstract]
Number of shares authorized to be repurchased (in shares)		14,000,000.0
Stock repurchased during the period (in shares)		1,300,000
Stock repurchased during the period (in USD per share)		$ 62.9	$ 51.8
Shares with remaining authorization for repurchase under stock repurchase plan (in shares)		5,800,000
Cash dividend declared per common share (in USD per share)	$ 0.180