Shareholders' Equity (Reclassification out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (5.6)	$ (5.9)	$ (11.3)	$ (12.6)
Tax impact	(19.2)	(11.4)	(31.4)	66.1
Total (income), net of tax	(55.1)	(50.3)	(90.5)	175.9
Reclassification From Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	(1.5)	(1.9)	(2.8)	277.6
Reclassification From Accumulated Other Comprehensive Loss [Member] | Derivative Gain (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Tax impact	0.5	0.3	0.9	0.4
Total (income), net of tax	(1.7)	(1.2)	(3.2)	(1.4)
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	(2.2)	(1.5)	(4.1)	(1.8)
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)	(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	0.3	(0.9)	0.7	1.4
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 loss (income), before tax	0.3	(0.9)	0.6	375.7
Income tax expense	(0.1)	0.2	(0.2)	(96.7)
Total loss (income), net of tax	$ 0.2	$ (0.7)	$ 0.4	$ 279.0