Pension and Post retirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Components of net periodic benefit cost [Abstract]
Estimated full year cash contributions to pension plan	$ 21
Pension Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	1.4	2.3
Interest cost	3.7	5.0
Expected return on plan assets	(3.8)	(5.7)
Amortization of prior service cost	0.2	0.2
Amortization of net (gain) loss	2.2	2.1
Net periodic benefit cost	3.7	3.9
Post-retirement Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	0.3	0.3
Interest cost	1.0	0.9
Expected return on plan assets	0	0
Amortization of prior service cost	0	0.5
Amortization of net (gain) loss	0.5	0.1
Net periodic benefit cost	$ 1.8	$ 1.8