Benefit Plans - Net Periodic Benefit Cost and Other Comprehensive (Loss) Income, Before Income Tax Effects (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits | U.S. Plans
Net Periodic Benefit Cost (Income):
Service cost	$ 5.8	$ 0.0	$ 0.0
Interest cost	9.5	2.2	2.1
Expected return on plan assets	(12.0)	(2.2)	(4.7)
Amortization of prior-service cost	0.0	0.0	0.0
Amortization of net actuarial loss	0.0	0.1	0.0
Net periodic benefit cost (income)	3.3	0.1	(2.6)
Loss due to settlement	0.0	0.0	0.0
Total net periodic benefit cost (income) recognized	3.3	0.1	(2.6)
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss):
Net actuarial (gain) loss	(6.4)	(0.9)	5.8
Amortization of net actuarial loss	0.0	(0.1)	0.0
Prior service cost	0.0	0.0	0.0
Amortization of prior service cost	0.0	0.0	0.0
Effect of foreign currency exchange rate changes	0.0	0.0	0.0
Total recognized in other comprehensive income (loss)	(6.4)	(1.0)	5.8
Total recognized in net periodic benefit (income) cost and other comprehensive income (loss)	(3.1)	(0.9)	3.2
Pension Benefits | Non-U.S. Plans
Net Periodic Benefit Cost (Income):
Service cost	3.8	1.5	1.8
Interest cost	6.1	7.7	7.5
Expected return on plan assets	(11.0)	(10.3)	(11.6)
Amortization of prior-service cost	0.1	0.1	0.0
Amortization of net actuarial loss	2.9	2.0	1.8
Net periodic benefit cost (income)	1.9	1.0	(0.5)
Loss due to settlement	0.0	0.0	0.0
Total net periodic benefit cost (income) recognized	1.9	1.0	(0.5)
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss):
Net actuarial (gain) loss	16.3	10.9	2.9
Amortization of net actuarial loss	(2.9)	(2.0)	(1.8)
Prior service cost	0.0	0.0	3.7
Amortization of prior service cost	(0.1)	(0.1)	0.0
Effect of foreign currency exchange rate changes	4.2	1.1	(2.8)
Total recognized in other comprehensive income (loss)	17.5	9.9	2.0
Total recognized in net periodic benefit (income) cost and other comprehensive income (loss)	19.4	10.9	1.5
Other Postretirement Benefits
Net Periodic Benefit Cost (Income):
Service cost	0.0	0.0	0.0
Interest cost	0.5	0.1	0.1
Expected return on plan assets	0.0	0.0	0.0
Amortization of prior-service cost	0.0	0.0	0.0
Amortization of net actuarial loss	0.0	0.0	0.0
Net periodic benefit cost (income)	0.5	0.1	0.1
Loss due to settlement	(0.3)	0.0	0.0
Total net periodic benefit cost (income) recognized	0.8	0.1	0.1
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss):
Net actuarial (gain) loss	2.0	0.4	(0.1)
Amortization of net actuarial loss	0.0	0.0	0.0
Prior service cost	(1.6)	0.0	0.0
Amortization of prior service cost	0.0	0.0	0.0
Effect of foreign currency exchange rate changes	0.0	0.0	0.1
Total recognized in other comprehensive income (loss)	0.4	0.4	0.0
Total recognized in net periodic benefit (income) cost and other comprehensive income (loss)	$ 1.2	$ 0.5	$ 0.1