Pension and Post-Retirement Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.4	$ 1.3
Interest cost	3.1	3.2
Expected return on plan assets	(4.7)	(5.4)
Amortization of prior service cost	0.0	0.1
Recognized actuarial loss	2.3	2.1
Settlements and curtailments	0.0	0.3
Net periodic benefit cost	2.1	1.6
Other Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.0	0.0
Interest cost	0.0	0.0
Expected return on plan assets	0.0	0.0
Amortization of prior service cost	(0.3)	(0.6)
Recognized actuarial loss	0.3	0.3
Settlements and curtailments	0.0	0.0
Net periodic benefit cost	$ 0.0	$ (0.3)