Postretirement and Other Benefits - Net Pension Benefit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
United States | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0.0	$ 0.0	$ 0.0
Interest cost	4.6	4.3	4.8
Expected return on plan assets	(5.8)	(5.8)	(6.4)
Amortizations and other	2.0	3.2	3.2
Net periodic benefit cost	0.8	1.7	1.6
United States | OPEB Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.0	0.0	0.0
Interest cost	0.1	0.1	0.1
Expected return on plan assets	0.0	0.0	0.0
Amortizations and other	0.0	0.1	0.2
Net periodic benefit cost	0.1	0.2	0.3
France | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1.0	1.1	1.1
Interest cost	0.4	0.4	0.4
Expected return on plan assets	(0.1)	(0.1)	(0.2)
Amortizations and other	0.9	1.1	1.4
Net periodic benefit cost	$ 2.2	$ 2.5	$ 2.7