PENSION AND POSTRETIREMENT BENEFITS - Components of Pension and Postretirement Plan Costs (Benefits) (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 29, 2021	Aug. 30, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Total pension cost (benefit)	$ (10.5)	$ (7.8)
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost	2.7	3.1
Interest cost	20.8	21.7
Expected return on plan assets	(36.4)	(35.0)
Amortization of prior service cost (benefit)	0.5	0.6
Total pension cost (benefit)	(12.4)	(9.6)
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost	0.0	0.1
Interest cost	0.3	0.3
Amortization of prior service cost (benefit)	(0.5)	(0.5)
Recognized net actuarial gain	(0.8)	(0.9)
Total pension cost (benefit)	(1.0)	(1.0)
Multi-employer plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Total pension cost (benefit)	$ 1.9	$ 1.8