Long-term Employee Benefits - Schedule of Net Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss:
Net actuarial (gain) loss, net	$ 6.4	$ (31.3)	$ 28.9
Pension Plan [Member]
Net periodic benefit cost:
Service cost	8.8	9.0	10.7
Interest cost	13.1	13.8	15.1
Expected return on plan assets	(16.1)	(15.0)	(12.6)
Amortization of actuarial loss, net	(1.3)	(1.4)	(0.4)
Amortization of prior service credit	(0.1)	0.0	0.0
Curtailment gain	(0.7)	0.0	(1.1)
Settlement (gain) loss	0.6	0.2	(0.5)
Special termination benefit loss	0.0	1.0	0.2
Net periodic benefit cost	6.9	10.4	12.2
Changes in plan assets and benefit obligations recognized in other comprehensive (income) loss:
Net actuarial (gain) loss, net	6.7	(20.6)	27.7
Amortization of actuarial loss, net	(1.3)	(1.4)	(0.4)
Prior service (credit) cost	0.8	(1.2)	0.0
Amortization of prior service credit	0.1	0.0	0.0
Curtailment gain	0.7	0.0	1.1
Settlement gain (loss)	(0.6)	(0.2)	0.5
Other adjustments	0.0	(7.9)	0.0
Total (gain) loss recognized in other comprehensive (income) loss	6.4	(31.3)	28.9
Total recognized in net periodic benefit cost and comprehensive (income) loss	$ 13.3	$ (20.9)	$ 41.1