PENSION AND POSTRETIREMENT BENEFITS (Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 23, 2014	Feb. 24, 2013	Feb. 23, 2014	Feb. 24, 2013
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0.1	$ 0.2	$ 0.5	$ 0.4
Interest cost	2.5	2.6	7.3	7.6
Amortization of prior service cost	(1.8)	(2.1)	(5.4)	(6.3)
Recognized net actuarial loss	1.6	1.5	5.0	4.5
Total benefit cost	2.4	2.2	7.4	6.2
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	22.3	20.6	66.8	60.9
Interest cost	37.7	37.6	113.3	110.8
Expected return on plan assets	(63.3)	(54.1)	(189.7)	(158.6)
Amortization of prior service cost	1.1	1.0	2.9	2.6
Curtailment loss	0	0	0	0.8
Benefit cost - Company plans	(2.2)	5.1	(6.7)	16.5
Multiemployer Plan, Period Contributions	2.7	1.9	9.4	6.2
Total benefit cost	$ 0.5	$ 7.0	$ 2.7	$ 22.7