PENSION AND POSTRETIREMENT BENEFITS (Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Feb. 24, 2013	Feb. 26, 2012	Feb. 24, 2013	Feb. 26, 2012
Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0.2	$ 0.1	$ 0.4	$ 0.4
Interest cost	2.6	3.1	7.6	10.0
Amortization of prior service cost	(2.1)	(3.9)	(6.3)	(9.7)
Recognized net actuarial loss	1.5	2.1	4.5	5.6
Total benefit cost	2.2	1.4	6.2	6.3
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	20.6	17.2	60.9	51.4
Interest cost	37.6	37.2	110.8	111.6
Expected return on plan assets	(54.1)	(48.9)	(158.6)	(146.7)
Amortization of prior service cost	1.0	0.8	2.6	2.3
Curtailment loss	0	0	0.8	0
Benefit cost - Company plans	5.1	6.3	16.5	18.6
Pension benefit cost - multi-employer plans	1.9	1.7	6.2	6.6
Total benefit cost	$ 7.0	$ 8.0	$ 22.7	$ 25.2

Benefit cost.

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- Definition

Multiemployer Plan, Period Expense

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Amount of gain (loss) from a decision to temporarily deviate from the substantive plan, or from a change in benefit obligation or plan asset value from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover or salary scale.

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The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

+ References

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- Definition

An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets.

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- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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- Definition

The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

+ References

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The amount of net gain (loss) recognized in net periodic benefit cost as a result of an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

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-Glossary Plan Curtailment

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- Definition

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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