Accumulated Other Comprehensive Loss (Reclassification Out Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-operating expenses	$ 24.5			$ 25.3			$ 39.6	$ 41.4
Tax benefit	24.4			11.8			68.2	34.0
Total reclassifications for the period, net of tax	(74.5)	$ (80.3)	$ (47.3)	(34.6)	$ (37.1)	$ (21.5)	(202.1)	(93.2)
Non-cash pension settlement charge							16.7	17.7
Reclassification out of AOCI | Actuarial Losses Recognized
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-operating expenses	25.3			25.3			42.6	40.4
Tax benefit	(6.5)			(6.5)			(11.0)	(10.4)
Total reclassifications for the period, net of tax	$ 18.8			$ 18.8			$ 31.6	$ 30.0