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		6 Months Ended
	Nov. 25, 2018	Nov. 26, 2017	Nov. 25, 2018	Nov. 26, 2017
Numerator:
Net income attributable to Lamb Weston Holdings, Inc.	$ 119.0	$ 76.6	$ 226.8	$ 160.0
Less: Increase in redemption value of noncontrolling interests in excess of earnings allocated	10.0	0.5	10.9	1.3
Net income available to Lamb Weston common stockholders	$ 109.0	$ 76.1	$ 215.9	$ 158.7
Denominator:
Basic weighted average common shares outstanding	146.6	146.3	146.5	146.3
Add: Dilutive effect of employee incentive plans	0.8	0.6	0.8	0.5
Diluted weighted average common shares outstanding	147.4	146.9	147.3	146.8
Earnings per share
Basic (in dollars per share)	$ 0.74	$ 0.52	$ 1.47	$ 1.08
Diluted (in dollars per share)	$ 0.74	$ 0.52	$ 1.47	$ 1.08