Long-term Employee Benefits - Schedule of Net Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Plan [Member]
Net periodic benefit cost:
Service cost	$ 3.3	$ 3.8	$ 6.4	$ 8.4
Interest cost	4.6	6.0	9.2	12.0
Expected return on plan assets	(3.6)	(3.7)	(7.3)	(7.4)
Amortization of actuarial (gain) loss, net	0.2	(0.1)	0.5	(0.2)
Amortization of prior service credit, net	0.0	0.0	(0.1)	0.0
Net periodic benefit (gain) cost	4.5	6.0	8.7	12.8
Other Postretirement Benefit Plan [Member]
Net periodic benefit cost:
Service cost	0.0	0.1	0.0	0.1
Interest cost	0.0	0.0	0.0	0.1
Amortization of prior service credit, net	(1.0)	0.0	(1.9)	0.0
Net periodic benefit (gain) cost	$ (1.0)	$ 0.1	$ (1.9)	$ 0.2