Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	$ (131.6)	$ (137.6)	$ (145.2)	$ (153.7)
Cumulative translation adjustments	(243.9)	(210.6)	(306.0)	(270.0)
Accumulated Other Comprehensive Income (Loss), Debt Securities, Available-for-sale, Adjustment, after Tax	0.0	0.0	0.0	(0.3)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(375.5)	(348.2)	(451.2)	(424.0)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	6.0	7.6	8.5
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(33.3)	95.4	(36.0)
Realized loss on investing securities, net of tax benefit of $0.0, $0.0, and $0.0, respectively	0.0	0.0	0.3
Other Comprehensive Income (Loss), Net of Tax	(27.3)	103.0	(27.2)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(375.5)	(348.2)	(451.2)	$ (424.0)
Other Comprehensive Income (Loss), Net of Tax	$ (27.3)	$ 103.0	$ (27.2)