Pension and Postretirement Plans Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Pension Plan [Member]
Prior service cost recognized:
Reclassification adjustments	$ 0.2	$ (0.4)
Prior service credit	0	0
Actuarial (loss) gain recognized:
Reclassification adjustments	17.3	22.0
Actuarial (loss) gain arising during the period	(57.5)	67.5
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Prior service cost (benefit)	0.2
Actuarial loss	20.9
Total	21.1
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service (cost) benefit, net of tax of $0.2, $0.3, $(21.3), $(26.8)	(0.5)	(0.6)
Actuarial loss, net of tax of $91.5, $77.2, $29.3, $26.6	(160.7)	(134.8)
Total	(161.2)	(135.4)
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax Effect [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Prior Service (Cost) Benefit, Tax Effect	0.2	0.3
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), Tax Effect	91.5	77.2
Other Postretirement Benefit Plan [Member]
Prior service cost recognized:
Reclassification adjustments	(15.4)	(14.1)
Prior service credit	0	17.4
Actuarial (loss) gain recognized:
Reclassification adjustments	5.4	5.6
Actuarial (loss) gain arising during the period	(12.9)	20.0
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Prior service cost (benefit)	(15.4)
Actuarial loss	6.2
Total	(9.2)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service (cost) benefit, net of tax of $0.2, $0.3, $(21.3), $(26.8)	38.5	48.4
Actuarial loss, net of tax of $91.5, $77.2, $29.3, $26.6	(50.9)	(46.1)
Total	(12.4)	2.3
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax Effect [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Prior Service (Cost) Benefit, Tax Effect	(21.3)	(26.8)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), Tax Effect	$ 29.3	$ 26.6

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Amount of gain (loss) included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

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Amount of prior service cost (credit) included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

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The total tax effect of net gains (losses) included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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The total tax effect of prior service (costs) benefits included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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The total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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After tax net amount of gain (loss) that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases (decreases) in other comprehensive income as they arise.

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Amount after tax of cost (credit) due to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as a component of net periodic benefit cost.

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Amount before tax, after reclassification adjustments, of prior service cost (credit) that has not been recognized in the income statement.

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Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

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Amount before tax of cost (credit) of benefit changes attributable to plan participants' prior service resulting from a plan amendment or plan initiation that has not been recognized in net periodic benefit cost (credit).

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Amount before tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit.

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Amount before tax of reclassification adjustment from accumulated other comprehensive income (loss) for actuarial gain (loss) related to pension and other postretirement benefit plans.

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