Pension and Post retirement Plans (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Pension Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	$ 2.2	$ 1.9	$ 6.6	$ 5.8
Interest cost	5.0	4.9	15.0	14.6
Expected return on plan assets	(5.7)	(5.1)	(17.1)	(15.4)
Amortization of prior service cost	0.2	0.2	0.6	0.5
Amortization of net (loss) gain	2.2	2.0	6.6	6.1
Net periodic benefit cost	3.9	3.9	11.7	11.6
Estimated full year net periodic benefit cost			15.5
Estimated full year cash contributions to pension plan			4
Post-retirement Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	0.3	0.2	0.9	0.7
Interest cost	0.9	0.9	2.8	2.5
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0.2	0.2
Amortization of net (loss) gain	0.5	0	1.5	0.1
Net periodic benefit cost	1.7	1.1	5.4	3.5
Estimated full year net periodic benefit cost			$ 6.9