Pension and Post retirement Plans (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Pension Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	$ 2.1	$ 1.8	$ 4.4	$ 3.9
Interest cost	5.0	4.8	10.0	9.7
Expected return on plan assets	(5.7)	(5.3)	(11.4)	(10.3)
Amortization of prior service cost	0.2	0.1	0.4	0.3
Amortization of net loss	2.3	1.4	4.4	4.1
Net periodic benefit cost	3.9	2.8	7.8	7.7
Estimated full year net periodic benefit cost			15.5
Estimated full year cash contributions to pension plan			5
Post-retirement Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	0.3	0.3	0.6	0.5
Interest cost	1.0	0.8	1.9	1.6
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0.1	0.1	0.2	0.2
Amortization of net loss	0.5	0	1.0	0.1
Net periodic benefit cost	1.9	1.2	3.7	2.4
Estimated full year net periodic benefit cost			$ 6.9