Accumulated Other Comprehensive Loss (Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			$ 892.9
Ending balance	$ 986.1		986.1
Amounts reclassified from accumulated other comprehensive loss, tax	(6.5)	$ (1.2)	(10.4)	$ (3.7)
Actuarial loss, tax	3.5		3.5
Foreign Currency
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(12.7)	(8.4)	(7.7)	(12.4)
Other comprehensive (loss) income before reclassifications	2.1	(1.2)	(2.9)	2.8
Amounts reclassified from accumulated other comprehensive income (net of tax $(6.5), $(1.2), $(10.4), and $(3.7))
Actuarial loss (net of tax of $3.5)
Net current-period other comprehensive (loss) income	2.1	(1.2)	(2.9)	2.8
Ending balance	(10.6)	(9.6)	(10.6)	(9.6)
Pension and Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(231.7)	(220.7)	(242.9)	(227.9)
Other comprehensive (loss) income before reclassifications
Amounts reclassified from accumulated other comprehensive income (net of tax $(6.5), $(1.2), $(10.4), and $(3.7))	18.8	3.6	30.0	10.8
Actuarial loss (net of tax of $3.5)	(10.2)		(10.2)
Net current-period other comprehensive (loss) income	8.6	3.6	19.8	10.8
Ending balance	(223.1)	(217.1)	(223.1)	(217.1)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(244.4)	(229.1)	(250.6)	(240.3)
Other comprehensive (loss) income before reclassifications	2.1	(1.2)	(2.9)	2.8
Amounts reclassified from accumulated other comprehensive income (net of tax $(6.5), $(1.2), $(10.4), and $(3.7))	18.8	3.6	30.0	10.8
Actuarial loss (net of tax of $3.5)	(10.2)		(10.2)
Net current-period other comprehensive (loss) income	10.7	2.4	16.9	13.6
Ending balance	$ (233.7)	$ (226.7)	$ (233.7)	$ (226.7)

Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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