EARNINGS PER SHARE - Computation of Basic and Diluted Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Aug. 27, 2017	Aug. 28, 2016
Numerator:
Net income attributable to Lamb Weston Holdings, Inc.	$ 83.4	$ 79.6
Less: Increase in redemption value of noncontrolling interests in excess of earnings allocated	0.8	0.5
Net income available to Lamb Weston common stockholders	$ 82.6	$ 79.1
Denominator:
Basic weighted average common shares outstanding	146.2	146.1
Add: Dilutive effect of employee incentive plans	0.6
Diluted weighted average common shares outstanding	146.8	146.1
Earnings per share
Basic (in dollars per share)	$ 0.56	$ 0.54
Diluted (in dollars per share)	$ 0.56	$ 0.54