Pension and Other Post-Retirement Benefits - Pension Obligations, Plan Assets, and Other Post-retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in Fair Value of Plan Assets
Plan assets at beginning of year	$ 435.6
Company contributions	2.2	$ 1.9	$ 1.8
Plan assets at end of year	369.8	435.6
Amount Recognized
Other liabilities	(75.8)	(84.4)
Accumulative other comprehensive loss:
After-tax amount recognized in accumulated other comprehensive loss	92.6	83.6	87.1	$ 99.9
Defined Benefit Pension [Member]
Change in Benefit Obligation
Benefit obligation at beginning of year	480.1	464.4
Service cost	8.2	6.5	6.1
Interest cost	14.7	15.4	15.3
Actuarial loss	40.9	(34.8)
Benefits paid	46.5	44.2
Effect of foreign exchange rate changes	(1.9)	3.2
Benefit obligation at end of year	413.7	480.1	464.4
Change in Fair Value of Plan Assets
Plan assets at beginning of year	435.6	413.5
Actual return on plan assets	(23.9)	61.3
Effect of exchange rate changes	(2.0)	3.4
Company contributions	6.6	1.6
Benefits paid	(46.5)	(44.2)
Plan assets at end of year	369.8	435.6	413.5
Funded Status at end of year	(43.9)	(44.5)
Amount Recognized
Other liabilities	(43.9)	(44.5)
Accumulative other comprehensive loss:
Net actuarial loss	125.2	132.5
Prior service credit (cost)	0.0	(0.1)
Accumulated other comprehensive loss	125.2	132.4
Defined Benefit Plan, Amounts Recognized in Balance Sheet and Accumulated Other Comprehensive Income (Loss)	81.3	87.9
After-tax amount recognized in accumulated other comprehensive loss	95.4	82.7
Retiree Health and Life [Member]
Change in Benefit Obligation
Benefit obligation at beginning of year	33.7	30.3
Service cost	0.2	0.2	0.2
Interest cost	1.0	1.1	0.9
Actuarial loss	5.0	(5.5)
Benefits paid	2.4	3.4
Effect of foreign exchange rate changes	0.0	0.0
Benefit obligation at end of year	27.5	33.7	30.3
Change in Fair Value of Plan Assets
Plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Effect of exchange rate changes	0.0	0.0
Company contributions	2.4	3.4
Benefits paid	(2.4)	(3.4)
Plan assets at end of year	0.0	0.0	$ 0.0
Funded Status at end of year	(27.5)	(33.7)
Amount Recognized
Other liabilities	(27.5)	(33.7)
Accumulative other comprehensive loss:
Net actuarial loss	(2.2)	2.8
Prior service credit (cost)	(1.4)	(1.6)
Accumulated other comprehensive loss	(3.6)	1.2
Defined Benefit Plan, Amounts Recognized in Balance Sheet and Accumulated Other Comprehensive Income (Loss)	(31.1)	(32.5)
After-tax amount recognized in accumulated other comprehensive loss	$ (2.8)	$ 0.9