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. 24, 2019	Nov. 25, 2018	Nov. 24, 2019	Nov. 25, 2018
Numerator:
Net income attributable to Lamb Weston Holdings, Inc.	$ 140.4	$ 119.0	$ 256.1	$ 226.8
Less: Increase in redemption value of noncontrolling interests in excess of earnings allocated, net of tax benefits		10.0		10.9
Net income available to Lamb Weston common stockholders	$ 140.4	$ 109.0	$ 256.1	$ 215.9
Denominator:
Basic weighted average common shares outstanding	146.2	146.6	146.2	146.5
Add: Dilutive effect of employee incentive plans	0.9	0.8	0.9	0.8
Diluted weighted average common shares outstanding	147.1	147.4	147.1	147.3
Earnings per share
Basic (in dollars per share)	$ 0.96	$ 0.74	$ 1.75	$ 1.47
Diluted (in dollars per share)	$ 0.95	$ 0.74	$ 1.74	$ 1.47