EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2021	Feb. 23, 2020	Feb. 28, 2021	Feb. 23, 2020
Numerator:
Net income	$ 66.1	$ 111.4	$ 252.3	$ 367.5
Net income available to common stockholders, basic	66.1	111.4	252.3	367.5
Net income available to common stockholders, diluted	$ 66.1	$ 111.4	$ 252.3	$ 367.5
Denominator:
Basic weighted average common shares outstanding (in shares)	146.5	146.2	146.4	146.2
Add: Dilutive effect of employee incentive plans (in shares)	0.7	1.0	0.7	0.9
Diluted weighted average common shares outstanding (in shares)	147.2	147.2	147.1	147.1
Earnings per share
Basic (in dollars per share)	$ 0.45	$ 0.76	$ 1.72	$ 2.51
Diluted (in dollars per share)	$ 0.45	$ 0.76	$ 1.72	$ 2.50