Pensions and Postretirement Benefits Other than Pensions (Components of the Company's Pension-Related Costs) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Total	$ (3.9)	$ (7.2)	$ (9.0)	$ (25.3)
Pension Costs [Member]
Service cost	10.3	19.0	44.0	55.2
Interest cost	20.2	29.7	63.2	89.3
Expected return on plan assets	(29.8)	(34.6)	(91.3)	(103.8)
Net amortization of prior service costs	1.3	1.2	4.0	3.6
Net amortization of plan net actuarial losses	11.4	14.0	33.0	40.7
Net periodic pension benefit cost	13.4	29.3	52.9	85.0
Net curtailment loss	0.1	(0.8)	3.7	(2.4)
Total	13.3	30.1	49.2	87.4
Pension Costs [Member] | Continuing Operations [Member]
Total
Pension Costs [Member] | Discontinued Operations [Member]
Total	0.4	7.4	3.7	21.1
Operating Income (Loss) [Member] | Pension Costs [Member] | Continuing Operations [Member]
Total	9.2	14.7	38.7	43.2
Other Nonoperating Income (Expense) [Member] | Pension Costs [Member] | Continuing Operations [Member]
Total	$ 3.7	$ 8.0	$ 6.8	$ 23.1