Pension and Other Post-Retirement Benefits (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components of pension and other post retirement benefit costs
Special termination benefits	$ 7.3
Defined Benefit Pension [Member]
Components of pension and other post retirement benefit costs
Service cost	7.4	$ 5.9	$ 6.7
Interest cost	19.6	20.7	18.4
Expected return on plan assets	(25.8)	(28.4)	(27.5)
Special termination benefits	7.3
Amortization of unrecognized prior service credit	(1.0)	(1.0)	(1.0)
Unrecognized net actuarial loss (gain)	14.8	11.3	14.9
Net periodic (benefit) cost	22.3	8.5	11.5
Retiree Health and Life [Member]
Components of pension and other post retirement benefit costs
Service cost	0.2	0.1	0.2
Interest cost	1.3	1.6	1.6
Expected return on plan assets	0.0	0.0	0.0
Special termination benefits	1.7
Amortization of unrecognized prior service credit	(0.1)	(0.1)	(0.1)
Unrecognized net actuarial loss (gain)	(0.2)	(0.1)	0.0
Net periodic (benefit) cost	$ 2.9	$ 1.5	$ 1.7