Benefits (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Pension Plan, Defined Benefit [Member]	Sep. 30, 2012 Pension Plan, Defined Benefit [Member]	Sep. 30, 2013 Pension Plan, Defined Benefit [Member]	Sep. 30, 2012 Pension Plan, Defined Benefit [Member]	Sep. 30, 2013 Other Postretirement Benefit Plan, Defined Benefit [Member]	Sep. 30, 2012 Other Postretirement Benefit Plan, Defined Benefit [Member]	Sep. 30, 2013 Other Postretirement Benefit Plan, Defined Benefit [Member]	Sep. 30, 2012 Other Postretirement Benefit Plan, Defined Benefit [Member]
Net Periodic Benefit Cost
Service cost				$ 3.7	$ 5.5	$ 11.0	$ 16.3	$ 2.5	$ 2.6	$ 7.5	$ 7.8
Interest cost				15.1	16.4	45.3	49.2	3.9	5.1	11.7	15.3
Expected return on plan assets				(23.9)	(22.5)	(71.8)	(67.3)	(5.4)	(4.8)	(16.0)	(14.4)
Amortization of:
Transition obligation								0	0	0	0.2
Prior service cost (credit)				0.5	0.5	1.7	1.7	(0.5)	(0.5)	(1.5)	(1.4)
Actuarial loss				13.6	10.2	40.8	30.4	1.0	1.9	2.8	5.4
Net Periodic Benefit Cost				9.0	10.1	27.0	30.3	1.5	4.3	4.5	12.9
Benefits (Textuals) [Abstract]
Pension and Other Postretirement Benefit Contributions	0	100.0
Estimated liability of Postemployment benefits	$ 4.0		$ 4.0

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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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The amount of the transition obligation or asset recognized in net periodic benefit cost.

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

+ References

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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 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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