Long-term Employee Benefits - Schedule of Net Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net periodic benefit cost:
Service cost	$ 1.8	$ 1.9
Interest cost	2.3	3.2
Expected return on plan assets	(3.2)	(3.5)
Amortization of actuarial loss, net	1.0	0.5
Plan curtailments	(1.2)	0.0
Net periodic benefit cost	$ 0.7	$ 2.1