Pensions and Postretirement Benefits Other than Pensions (Components of Net Periodic Postretirement Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Total			$ (21.7)	$ (24.2)
Postretirement Benefit Costs [Member]
Service cost	$ 0.8	$ 0.9	2.3	2.8
Interest cost	3.2	4.2	11.7	13.2
Net amortization of prior service gains	(2.2)	(2.3)	(6.5)	(6.7)
Net amortization of plan net actuarial losses	0.0	0.1	0.0	0.1
Total	1.8	2.9	7.5	9.4
Postretirement Benefit Costs [Member] | Segment, Continuing Operations [Member]
Total
Postretirement Benefit Costs [Member] | Discontinued Operations [Member]
Total	$ 0.1	$ 0.8	$ 1.4	$ 3.0