Retirement Benefit Plans Retirement Benefit Plans - Funded status of plans with ABO in excess of plan assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ (594.0)	$ (597.6)
Plan assets	423.3	431.0
Funded status of plan	(170.7)	(166.6)
Non-U.S. Plans:
Defined Benefit Plan Disclosure [Line Items]
Funded status of plan	(134.4)	(113.4)
Germany
Defined Benefit Plan Disclosure [Line Items]
Funded status of plan	(77.5)	(64.3)
United States
Defined Benefit Plan Disclosure [Line Items]
Funded status of plan	(53.0)	(64.9)
Other
Defined Benefit Plan Disclosure [Line Items]
Funded status of plan	$ (40.2)	$ (37.4)