Pension and Other Post-Retirement Benefit Plans (Contributions) (Details) - Pensions - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer contributions	$ 19.1	$ 3.0
International
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected employer contributions	19.9
U.S.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected employer contributions	$ 5.3