PENSION AND POSTRETIREMENT BENEFITS (Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Aug. 24, 2014	Aug. 25, 2013
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 22.1	$ 22.3
Interest cost	40.4	37.8
Expected return on plan assets	(67.0)	(63.2)
Amortization of prior service cost	0.9	0.9
Special termination benefits	6.9	0
Benefit cost — Company plans	3.3	(2.2)
Pension benefit cost — multi-employer plans	3.2	3.1
Total benefit cost	6.5	0.9
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.1	0.2
Interest cost	2.5	2.4
Amortization of prior service cost	(2.0)	(1.8)
Recognized net actuarial loss	0.9	1.7
Total benefit cost	$ 1.5	$ 2.5