Accumulated Other Comprehensive Loss (Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 1,880.5
Ending balance	1,981.9
Amounts reclassified from accumulated other comprehensive loss, tax	(0.4)	$ (0.1)
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(10.6)	(14.6)
Other comprehensive income (loss) before reclassifications	(4.0)	0.1
Amounts reclassified from accumulated other comprehensive income (net of tax)
Net current-period other comprehensive (loss) income	(4.0)	0.1
Ending balance	(14.6)	(14.5)
Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(167.3)	(138.2)
Other comprehensive income (loss) before reclassifications
Amounts reclassified from accumulated other comprehensive income (net of tax)	1.1	0.2
Net current-period other comprehensive (loss) income	1.1	0.2
Ending balance	(166.2)	(138.0)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(177.9)	(152.8)
Other comprehensive income (loss) before reclassifications	(4.0)	0.1
Amounts reclassified from accumulated other comprehensive income (net of tax)	1.1	0.2
Net current-period other comprehensive (loss) income	(2.9)	0.3
Ending balance	$ (180.8)	$ (152.5)