Accumulated Other Comprehensive Loss (Reclassification Out Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-operating expenses	$ 7.3		$ 8.6		$ 15.1	$ 16.1
Tax benefit	27.6		13.5		43.8	22.2
Total reclassifications for the period, net of tax	(80.3)	$ (47.3)	(37.1)	$ (21.5)	(127.6)	(58.6)
Reclassification out of AOCI | Actuarial Losses Recognized
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-operating expenses	8.4		7.7		17.3	15.1
Tax benefit	(2.2)		(2.0)		(4.5)	(3.9)
Total reclassifications for the period, net of tax	$ 6.2		$ 5.7		$ 12.8	$ 11.2