Goodwill and Other Intangible Assets - Goodwill Rollforward (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 169.2us-gaap_Goodwill	$ 23.8us-gaap_Goodwill	$ 168.9us-gaap_Goodwill	$ 0us-gaap_Goodwill
Intangible Assets, Net (Excluding Goodwill)	193.4	62.4	197.5	20.7
Goodwill, Acquired During Period	0.3us-gaap_GoodwillAcquiredDuringPeriod	23.8us-gaap_GoodwillAcquiredDuringPeriod
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	2.8	42.4
Disposition of Goodwill through disposition of business	0	(0.4)
Amortization of Intangible Assets	$ (6.9)us-gaap_AmortizationOfIntangibleAssets	$ (0.3)us-gaap_AmortizationOfIntangibleAssets

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

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- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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Disposition of Goodwill through disposition of business

+ References

No definition available.

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