SEGMENTS (Details) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 26, 2017 USD ($)	Feb. 28, 2016 USD ($)	Feb. 26, 2017 USD ($) segment	Feb. 28, 2016 USD ($)
SEGMENTS.
Number of operating segments | segment			4
Revenue information
Total net sales	$ 768.5	$ 728.7	$ 2,335.5	$ 2,216.8
Product contribution margin	202.6	177.6	571.5	467.3
Equity method investment earnings	12.7	36.1	29.5	56.3
Total product contribution margin plus equity method investment earnings	215.3	213.7	601.0	523.6
Other selling, general and administrative expenses	57.4	50.3	175.8	145.9
Interest expense, net	(26.3)	(1.5)	(34.5)	(4.3)
Income tax expense	44.0	53.2	129.0	124.2
Net income	87.6	108.7	261.7	249.2
Less: Income attributable to noncontrolling interests	3.4	1.3	10.7	6.5
Net income attributable to Lamb Weston Holdings, Inc.	84.2	107.4	251.0	242.7
Non-cash gain related to settlement of pension plan		17.7		17.7
Pretax professional fees expenses	5.1	0.7	23.8	0.7
Global
Revenue information
Total net sales	391.6	381.4	1,203.4	1,152.5
Product contribution margin	93.2	85.6	259.1	219.9
Foodservice
Revenue information
Total net sales	242.2	219.9	753.0	691.4
Product contribution margin	84.1	64.8	243.8	182.7
Retail
Revenue information
Total net sales	99.7	98.5	285.8	278.0
Product contribution margin	23.1	23.2	63.6	51.8
Other
Revenue information
Total net sales	35.0	28.9	93.3	94.9
Product contribution margin	$ 2.2	$ 4.0	$ 5.0	$ 12.9