Retirement and Other Postretirement Benefit Plans - Schedule of Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income Loss (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Postretirement Plans
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Loss
Net loss (gain)	$ (0.5)	$ 0.1
Amortization of actuarial (losses) gains	1.0	1.1
Total recognized in other comprehensive loss, (pre-tax)	0.5	1.2
U.S. Plans \| Defined Benefit Retirement Plans
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Loss
Net loss (gain)	1.6	0.9
Total recognized in other comprehensive loss, (pre-tax)	1.6	0.9
European Plans \| Defined Benefit Retirement Plans
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Loss
Net loss (gain)	20.2	8.3
Amortization of actuarial (losses) gains	(0.5)	(0.3)
Prior service cost		(0.1)
Effect of foreign exchange	1.7	0.8
Total recognized in other comprehensive loss, (pre-tax)	$ 21.4	$ 8.7

Defined benefit plan amounts recognized in other comprehensive income amortization of actuarial gain losses before tax.

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- Definition

Represents the effect of change in the exchange rate before tax recognized in other comprehensive income, including amounts arising during the period and reclassification adjustments of other comprehensive income as a result of being recognized as components of net periodic benefit cost for the period.

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Amount, before tax, after reclassification adjustment, of increase (decrease) in accumulated other comprehensive income from gain (loss) of defined benefit plan.

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Amount, before tax, after reclassification adjustment, of (increase) decrease in accumulated other comprehensive income from prior service cost (credit) of defined benefit plan.

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