Accumulated Other Comprehensive Loss (Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 1,520.0
Ending balance	1,644.5
Amounts reclassified from accumulated other comprehensive loss, tax	(0.1)	$ (1.4)
Foreign Currency
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(14.6)	(5.0)
Other comprehensive income before reclassifications	0.1	2.1
Amounts reclassified from accumulated other comprehensive income (net of tax $(0.1) and $(1.4))
Net current-period other comprehensive (loss) income	0.1	2.1
Ending balance	(14.5)	(2.9)
Pension and Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(138.2)	(175.5)
Other comprehensive income before reclassifications
Amounts reclassified from accumulated other comprehensive income (net of tax $(0.1) and $(1.4))	0.2	4.4
Net current-period other comprehensive (loss) income	0.2	4.4
Ending balance	(138.0)	(171.1)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(152.8)	(180.5)
Other comprehensive income before reclassifications	0.1	2.1
Amounts reclassified from accumulated other comprehensive income (net of tax $(0.1) and $(1.4))	0.2	4.4
Net current-period other comprehensive (loss) income	0.3	6.5
Ending balance	$ (152.5)	$ (174.0)