Pension and Other Post-Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Post-Retirement Benefit Plans, Reclassification adjustments into earnings	$ 2.3	$ 2.0	$ 2.3
Defined Benefit Plan, Special Termination Benefits	0.0			$ 0.0	$ 0.0	$ 0.0
Defined Benefit Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1.5			1.9	4.5	5.6
Interest cost	3.9			4.9	11.8	14.8
Expected return on plan assets	(6.5)			(6.4)	(19.5)	(19.3)
Defined Benefit Plan, Special Termination Benefits	5.7				5.7
Unrecognized prior service credit	(0.2)			(0.3)	(0.7)	(0.8)
Unrecognized net actuarial loss	2.6			3.7	7.7	11.1
Net expense	7.0			3.8	9.5	11.4
Retiree Health and Life [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1			0.1	0.2	0.2
Interest cost	0.2			0.3	0.7	1.0
Expected return on plan assets	0.0			0.0	0.0	0.0
Unrecognized prior service credit	(0.1)			(0.1)	(0.2)	(0.2)
Unrecognized net actuarial loss	0.0			0.0	(0.2)	0.0
Net expense	$ 0.2			$ 0.3	$ 0.5	$ 1.0