Retirement Benefits Retirement Benefits - Venezuela Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) VEF / $	Dec. 31, 2016 USD ($) VEF / $	Dec. 31, 2015 USD ($) VEF / $	Dec. 31, 2033	Mar. 31, 2016 VEF / $
Venezuela
Defined Benefit Plan Disclosure [Line Items]
Decline in rate		59.00%
Venezuelan bolívar fuerte | Venezuela
Defined Benefit Plan Disclosure [Line Items]
Inflation rate	900.00%
Decline in rate	80.00%	70.00%
Exchange rate remeasurement | VEF / $	3,345	674	199		273
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligations	$ 301.5	$ 267.3	$ 262.8
Net periodic postretirement cost	$ 25.0	$ 21.7	$ 23.7
Discount rate	3.50%	3.70%	5.10%
Projected benefit payments	$ 86.8
Non-U.S. Plans | Venezuela
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligations	4.3	$ 5.6	$ 4.1
Net periodic postretirement cost	$ 7.5	$ 2.9	$ 2.5
Discount rate	4.00%
Projected benefit payments	$ 38,740,810.4
Forecast | Venezuelan bolívar fuerte | Venezuela
Defined Benefit Plan Disclosure [Line Items]
Decline in rate				4.00%