Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Accumulated other comprehensive loss, net of tax
Foreign currency translation	$ (383.4)	$ (275.5)	$ (385.4)	$ (291.1)
Pension and other postretirement liability adjustment, net of deferred tax effect	(138.2)	(100.4)	(140.1)	(103.4)
Accumulated other comprehensive loss	(521.6)	(375.9)	$ (525.5)	$ (394.5)
Tax effect of pension liability adjustment	46.7	47.3
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	2.6	4.1
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	(0.7)	(1.1)
Other comprehensive income, before reclassification, foreign currency translation	2.0	15.6
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	0.0	0.0
Other comprehensive income, reclassification adjustment, foreign currency translation	0.0	0.0
Other comprehensive income, reclassification, pension	1.9	3.0
Translation adjustments	2.0	15.6
Pension and other postretirement liability adjustments, net of tax	1.9	3.0
Other comprehensive income (loss)	3.9	18.6
Before reclassification [Member]
Accumulated other comprehensive loss, net of tax
Other comprehensive income (loss)	2.0	15.6
Reclassified [Member]
Accumulated other comprehensive loss, net of tax
Other comprehensive income (loss)	$ 1.9	$ 3.0