Pension and Postretirement Benefit Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2014
Pension Plans, Defined Benefit [Member]
Components of net periodic benefit cost
Service cost for benefits earned	$ 0.5	$ 0.6
Interest cost on projected benefit obligation	11.3	10.6
Expected return on plan assets	(13.5)	(14.9)
Amortization of prior service cost (credit)	0.3	0.2
Amortization of actuarial loss	7.6	16.4
Net periodic benefit cost	6.2	12.9
Funding threshhold	80.00%
Employer contributions to pension plan	0.8
Estimated contribution in 2014 to pension plan			13
Other Postretirement Benefit Plan, Defined Benefit [Member]
Components of net periodic benefit cost
Service cost for benefits earned	3.1	3.9
Interest cost on projected benefit obligation	9.1	10.5
Amortization of prior service cost (credit)	0.3	(0.4)
Amortization of actuarial loss	3.6	6.0
Net periodic benefit cost	16.1	20.0
Increase in accumulated postretirement benefit obligation, before tax	27.6
Defined benefit plans estimated additional incremental contributions in 2014			$ 2.0