PENSION PLANS AND RETIREMENT BENEFITS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Mar. 31, 2010
PENSION PLANS AND RETIREMENT BENEFITS [Abstract]
Contribution to an individual retirement account as a percentage of employee's eligible compensation under age 45 (in hundredths)	5.00%		5.00%
Contribution to an individual retirement account as a percentage of employee's eligible compensation age 45 and older (in hundredths)	7.50%		7.50%
Defined contribution pension plans expense	$ 3.8	$ 3.2	$ 7.4	$ 7.2
Pension Benefits [Member]
Components of Net Periodic Benefit (Income) Cost
Service cost	1.6	1.4	3.2	3.0
Interest cost	23.5	24.7	47.2	49.5
Expected return on plans' assets	(34.9)	(34.6)	(69.8)	(69.3)
Amortization of prior service cost	0.1	0.1	0.2	0.3
Recognized actuarial loss	3.6	3.1	7.5	6.4
Curtailments	1.1	0	1.1	0
Net periodic benefit (income) cost	(5.0)	(5.3)	(10.6)	(10.1)
Employer's contribution to defined benefit pension			0.5	4.9
Withdrawal from a multi-employer defined benefit pension plan					1.3
Other Postretirement Benefits [Member]
Components of Net Periodic Benefit (Income) Cost
Service cost	0.3	0.3	0.7	0.7
Interest cost	1.0	1.0	1.9	2.0
Expected return on plans' assets	0	0	0	0
Amortization of prior service cost	0	0	(0.1)	(0.1)
Recognized actuarial loss	0.7	0.7	1.4	1.4
Curtailments	0	0	0	0
Net periodic benefit (income) cost	$ 2.0	$ 2.0	$ 3.9	$ 4.0

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Contribution to an individual retirement account as a percentage of employee's eligible compensation age 45 and older.

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Contribution to an individual retirement account as a percentage of employee's eligible compensation under age 45.

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The net increase or decrease of changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

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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.

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The increase in the fair value of plan assets from contributions made by the employer.

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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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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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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.

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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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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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The amount of the cost recognized during the period for defined contribution plans.

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Amount of a recognized obligation to a multiemployer plan in the event that the employer withdraws from the plan. In some situations, withdrawal from a multiemployer plan may result in an employer having an obligation to the plan for a portion of the unfunded benefit obligation of the pension plans and other postretirement benefit plans.

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