Pension and Other Postretirement Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 5.3	$ 4.9
Expected return on plan assets	(5.8)	(5.2)
Recognized net actuarial loss	2.8	2.5
Net periodic pension cost	2.3	2.2
Postretirement Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	0.1	0.1
Recognized net actuarial loss		0.1
Amortization of prior service cost		(0.1)
Net periodic pension cost	$ 0.1	$ 0.1