Pension and Other Postretirement Benefit Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Curtailment gain			$ (1.8)
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost - benefits earned during the period	$ 0.2	$ 0.2		$ 0.6	$ 0.9
Interest cost	7.4	7.4		22.2	22.0
Expected return on plan assets	(7.4)	(8.0)		(22.4)	(23.7)
Recognized net actuarial loss	2.8	3.1		8.4	10.9
Curtailment gain					(1.8)
Net periodic pension cost (benefit)	3.0	2.7		8.8	8.3
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	0.2	0.1		0.4	0.4
Recognized net actuarial loss				0.1	0.1
Amortization of prior service cost	(0.3)	(0.3)		(1.0)	(1.0)
Net periodic pension cost (benefit)	$ (0.1)	$ (0.2)		$ (0.5)	$ (0.5)