Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Unrecognized tax benefits, net	$ 85.1
Unrecognized tax benefits that would impact effective tax rate	62.4
Deferred Tax Asset/Liability Related to Advanced Pricing Agreement			$ 44.0
Reconciliation of the total gross unrecognized tax benefits
Balance, January 1	91.1	$ 127.3
Additions based on tax positions related to current year	16.8	16.1
Unrecognized tax benefits, decrease resulting from prior period tax positions	(2.4)
Unrecognized tax benefits, increase resulting from prior period tax positions		1.6
Reductions for closure of tax audits and settlements	(19.9)	(45.7)
Reductions for lapse in statute of limitations	(0.8)	(5.0)
Unrecognized tax benefits, increase resulting from foreign currency translation	7.2
Unrecognized tax benefits, decrease resulting from foreign currency translation		(3.2)
Balance, December 31	92.0	91.1	$ 127.3
Income tax penalties and interest expense	6.4	3.2
Income tax penalties and interest accrued on unrecognized tax benefits	22.6	$ 16.0
Other Current Liabilities [Member]
Reconciliation of the total gross unrecognized tax benefits
Balance, December 31	$ 0.8