Shareholders' Equity (Reclassification out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (5.9)	$ (9.5)	$ (12.6)	$ (19.9)
Tax impact	(11.4)	(19.4)	66.1	(32.8)
Total (income) loss, net of tax	(50.3)	(54.5)	175.9	(93.6)
Reclassification From Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	(1.9)	2.5	277.6	5.1
Reclassification From Accumulated Other Comprehensive Loss [Member] | Derivative Gain (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Tax impact	0.3	(0.1)	0.4	(0.2)
Total (income) loss, net of tax	(1.2)	0.3	(1.4)	0.8
Reclassification From Accumulated Other Comprehensive Loss [Member] | Derivative Gain (Loss) [Member] | Interest Rate Swap Contracts, Before Tax [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(1.5)	0.4	(1.8)	1.0
Reclassification From Accumulated Other Comprehensive Loss [Member] | Prior Service Credit Amortization [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other non-operating (income) expense, net			(0.1)
Reclassification From Accumulated Other Comprehensive Loss [Member] | Amortization of Net Actuarial Loss [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other non-operating (income) expense, net	(0.9)	2.7	1.4	5.4
Reclassification From Accumulated Other Comprehensive Loss [Member] | Settlement [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other non-operating (income) expense, net			374.4
Reclassification From Accumulated Other Comprehensive Loss [Member] | Pension And Postretirement Adjustments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total (income) loss, before tax	(0.9)	2.7	375.7	5.4
Income tax expense	0.2	(0.5)	(96.7)	(1.1)
Total income (loss), net of tax	$ (0.7)	$ 2.2	$ 279.0	$ 4.3