Pension Plans and Other Postretirement Benefits (Components of net periodic benefit) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Benefits [Member]
Components of net periodic benefit cost
Service costs	$ 0.6	$ 0.5	$ 1.3	$ 1.1
Interest costs	0.5	0.6	1.0	1.1
Expected return on plan assets	(2.2)	(2.0)	(4.4)	(4.1)
Recognized net actuarial loss	0.2	0.2	0.3	0.5
Net periodic benefit (gains) costs	(0.9)	(0.7)	(1.8)	(1.4)
Postretirement Benefits [Member]
Components of net periodic benefit cost
Service costs	0	0	0	0
Interest costs	0.2	0.2	0.3	0.4
Expected return on plan assets	0	0	0	0
Recognized net actuarial loss	0.2	0.2	0.4	0.4
Net periodic benefit (gains) costs	$ 0.4	$ 0.4	$ 0.7	$ 0.8