Income Taxes - Unrecognized Tax Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Reconciliation of the total gross unrecognized tax benefits
Balance, January 1	$ 22.9us-gaap_UnrecognizedTaxBenefits	$ 25.8us-gaap_UnrecognizedTaxBenefits
Additions based on tax positions related to current year	19.3	1.7
Additions for tax positions of prior years	22.5	12.5
Reductions for closure of tax audits and settlements		(17.7)
Reductions for lapse in statute of limitations	(1.5)	(0.2)
Translation adjustment	(2.8)
Translation adjustment		0.8
Balance, December 31	60.4us-gaap_UnrecognizedTaxBenefits	22.9us-gaap_UnrecognizedTaxBenefits
Unrecognized tax benefits that would impact effective tax rate	56.1
Income tax penalties and interest expense	1.9	1.0
Income tax penalties and interest accrued on unrecognized tax benefits	$ 10.3	$ 8.4

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

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Amount of decrease in unrecognized tax benefits resulting from foreign currency translation.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from foreign currency translation.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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