Pension and Other Post-Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Accumulative other comprehensive loss:
After-tax amount recognized in accumulated other comprehensive loss	$ 85.8		$ 87.1
Defined Benefit Pension [Member]
Change in Benefit Obligation
Service cost	1.6	$ 1.6
Accumulative other comprehensive loss:
Defined Benefit Plan, Interest Cost	3.8	3.9
Defined Benefit Plan, Expected Return on Plan Assets	(6.0)	(6.5)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0.0	(0.2)
Defined Benefit Plan, Net Periodic Benefit Cost	1.7	1.4
Defined Benefit Plan, Amortization of Gains (Losses)	2.3	2.6
Other Postretirement Benefit Plan [Member]
Change in Benefit Obligation
Service cost	0.0	0.0
Accumulative other comprehensive loss:
Defined Benefit Plan, Interest Cost	0.2	0.3
Defined Benefit Plan, Expected Return on Plan Assets	0.0	0.0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0.0	(0.1)
Defined Benefit Plan, Net Periodic Benefit Cost	0.1	0.2
Defined Benefit Plan, Amortization of Gains (Losses)	$ (0.1)	$ 0.0