Pensions and Postretirement Benefits Other than Pensions (Components of Net Periodic Postretirement Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Total	$ (1.7)	$ (9.8)
Postretirement Benefit Costs [Member]
Defined Benefit Plan, Benefit Obligation, Divestiture	29.8
Service cost	0.6	0.6
Interest cost	2.6	3.9
Net amortization of prior service gains	0.0	(0.1)
Net amortization of plan net actuarial losses	(1.1)	(1.6)
Total	2.1	2.8
Postretirement Benefit Costs [Member] | Continuing Operations [Member]
Total
Postretirement Benefit Costs [Member] | Discontinued Operations [Member]
Total	0.5	0.7
Operating Income (Loss) [Member] | Postretirement Benefit Costs [Member] | Continuing Operations [Member]
Total	0.6	0.6
Other Nonoperating Income (Expense) [Member] | Postretirement Benefit Costs [Member] | Continuing Operations [Member]
Total	$ 1.0	$ 1.5