Long-term Employee Benefits - Schedule of Net Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Plan [Member]
Net periodic benefit (gain) cost:
Service cost	$ 2.7	$ 3.8	$ 9.1	$ 12.3
Interest cost	3.9	6.1	13.1	18.0
Expected return on plan assets	(3.7)	(3.9)	(11.0)	(11.3)
Amortization of actuarial (gain) loss, net	0.2	0.0	0.7	(0.2)
Amortization of prior service credit, net	0.0	0.0	(0.1)	0.0
Curtailment gain	0.0	(6.6)	0.0	(6.6)
Net periodic benefit gain	3.1	(0.6)	11.8	12.2
Other Postretirement Benefit Plan [Member]
Net periodic benefit (gain) cost:
Service cost	0.0	0.0	0.0	0.1
Interest cost	0.0	0.1	0.0	0.1
Amortization of prior service credit, net	(0.9)	(0.4)	(2.8)	(0.3)
Net periodic benefit gain	$ (0.9)	$ (0.3)	$ (2.8)	$ (0.1)