Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	18.70%	4.80%	11.10%	23.60%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount		$ 9.8
Net unrecognized tax benefit	$ 83.2		$ 83.2		$ 77.8
Income tax interest and penalties accrued	4.1		4.1
Deferred tax assets	$ 106.8		$ 106.8