Pensions and Postretirement Benefits Other than Pensions (Components of Net Periodic Postretirement Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Total			$ (9.7)	$ (14.4)
Postretirement Benefit Costs [Member]
Service cost	$ 0.7	$ 0.7	1.4	1.5
Interest cost	3.8	4.2	7.6	8.5
Net amortization of prior service gains	(1.0)	(2.1)	(2.0)	(4.3)
Net amortization of plan net actuarial losses	0.0	0.0	0.0	0.0
Total	3.5	2.8	7.0	5.7
Postretirement Benefit Costs [Member] | Segment, Continuing Operations [Member]
Total
Postretirement Benefit Costs [Member] | Discontinued Operations [Member]
Total	$ 0.8	$ 0.4	$ 1.6	$ 1.3