PENSION AND POSTRETIREMENT BENEFITS - Components of Pension Benefit and Other Postretirement Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 27, 2017	Aug. 28, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension benefit cost — multi-employer plans	$ (12.6)	$ (10.4)
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	12.7	16.7
Interest cost	28.2	30.0
Expected return on plan assets	(54.2)	(53.8)
Amortization of prior service cost	0.7	0.6
Benefit cost (benefit) — Company plans	(12.6)	(6.5)
Pension benefit cost — multi-employer plans	1.5	2.3
Total cost (benefit)	(11.1)	(4.2)
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.0	0.0
Interest cost	0.9	1.1
Amortization of prior service cost	(0.8)	(1.7)
Recognized net actuarial loss	0.0	0.1
Total cost (benefit)	$ 0.1	$ (0.5)