Accumulated Other Comprehensive Loss (Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			$ 1,880.5
Ending balance	$ 2,079.0		2,079.0
Amounts reclassified from accumulated other comprehensive loss, tax	(0.6)	$ (0.1)	(1.0)	$ (0.2)
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(14.6)	(14.5)	(10.6)	(14.6)
Other comprehensive (loss) income before reclassifications	(1.8)	3.5	(5.8)	3.6
Amounts reclassified from accumulated other comprehensive income (net of tax)
Net current-period other comprehensive (loss) income	(1.8)	3.5	(5.8)	3.6
Ending balance	(16.4)	(11.0)	(16.4)	(11.0)
Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(166.2)	(138.0)	(167.3)	(138.2)
Other comprehensive (loss) income before reclassifications
Amounts reclassified from accumulated other comprehensive income (net of tax)	1.7	0.2	2.8	0.4
Net current-period other comprehensive (loss) income	1.7	0.2	2.8	0.4
Ending balance	(164.5)	(137.8)	(164.5)	(137.8)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(180.8)	(152.5)	(177.9)	(152.8)
Other comprehensive (loss) income before reclassifications	(1.8)	3.5	(5.8)	3.6
Amounts reclassified from accumulated other comprehensive income (net of tax)	1.7	0.2	2.8	0.4
Net current-period other comprehensive (loss) income	(0.1)	3.7	(3.0)	4.0
Ending balance	$ (180.9)	$ (148.8)	$ (180.9)	$ (148.8)