Pension and Other Postemployment Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Defined Benefit Pension Plans [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 1.4	$ 1.1
Interest cost	1.4	1.2
Expected return on plan assets	(0.6)	(0.6)
Amortization of prior service cost	0.8	0.8
Amortization of actuarial (gains) losses	0.4	0.1
Net periodic benefit cost	3.4	2.6
Defined benefit pension plans, contributions by employer	0.5	0.6
Postemployment Arrangements [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost	1.0	1.0
Interest cost	1.2	1.2
Amortization of prior service cost	0.5	0.5
Amortization of actuarial (gains) losses	0.2	0.1
Net periodic benefit cost	$ 2.9	$ 2.8