Pension and Other Postretirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.6	$ 1.6
Interest cost	3.8	3.9
Expected return on plan assets	6.0	6.5
Unrecognized prior service credit	0.0	(0.2)
Unrecognized net actuarial loss	(2.3)	(2.6)
Net expense	1.7	1.4
Other Postretirement Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.0	0.0
Interest cost	0.2	0.3
Expected return on plan assets	0.0	0.0
Unrecognized prior service credit	0.0	(0.1)
Unrecognized net actuarial loss	0.1	0.0
Net expense	$ 0.1	$ 0.2