Benefits (Details) (USD $) In Millions	6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Jun. 30, 2011 Pension Plans, Defined Benefit [Member]	Jun. 30, 2010 Pension Plans, Defined Benefit [Member]	Jun. 30, 2011 Pension Plans, Defined Benefit [Member]	Jun. 30, 2010 Pension Plans, Defined Benefit [Member]	Jun. 30, 2011 Other Postretirement Benefit Plans, Defined Benefit [Member]	Jun. 30, 2010 Other Postretirement Benefit Plans, Defined Benefit [Member]	Jun. 30, 2011 Other Postretirement Benefit Plans, Defined Benefit [Member]	Jun. 30, 2010 Other Postretirement Benefit Plans, Defined Benefit [Member]
Net Periodic Benefit Cost
Service cost				$ 3.3	$ 4.9	$ 7.9	$ 11.8	$ 2.4	$ 2.8	$ 5.2	$ 5.6
Interest cost				17.1	16.4	33.8	33.8	5.1	5.1	10.4	10.5
Expected return on plan assets				(20.4)	(19.0)	(41.1)	(38.7)	(4.1)	(3.6)	(8.4)	(7.2)
Amortization of:
Transition obligation								0.1	0.1	0.2	0.2
Prior service cost (credit)				0.5	0.5	1.1	1.1	(0.5)	(2.9)	(1.0)	(5.9)
Actuarial loss				9.0	6.7	17.1	13.3	1.5	2.7	3.0	5.4
Net Periodic Benefit Cost				9.5	9.5	18.8	21.3	4.5	4.2	9.4	8.6
Benefits (Textuals) [Abstract]
Pension and Other Postretirement Benefit Contributions	122.4	0
Estimated liability of Postemployment benefits	$ 13.9		$ 14.8

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The amount of gains or losses recognized in net periodic benefit cost.

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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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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 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 cash or cash equivalents contributed during the reporting period by the entity to fund its pension plans and its non-pension postretirement benefit plans.

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Benefits

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