Pensions - Schedule of Amounts Recognized in Consolidated Balance Sheet (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
U.S. Benefit Plans
Amounts recognized in Total liabilities include:
Long-term pension and other post-retirement benefit liabilities	$ 47.3	$ 49.5
Net liability recorded	47.3	49.5
Amounts recognized in Accumulated other comprehensive loss include:
Net actuarial loss	80.2	84.1
Net amount recognized, pre-tax	80.2	84.1
Non-U.S. Benefit Plan
Amounts recognized in Total liabilities include:
Long-term pension and other post-retirement benefit liabilities	0.0	3.2
Net liability recorded	0.0	3.2
Amounts recognized in Accumulated other comprehensive loss include:
Net actuarial loss	17.8	18.8
Net amount recognized, pre-tax	$ 17.8	$ 18.8