Accumulated Other Comprehensive Loss (Reclassifications Out Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-operating expenses	$ 8.6		$ 6.3		$ 16.1	$ 12.9
Tax benefit	13.5		17.8		22.2	30.8
Total reclassifications for the period, net of tax	(37.1)	$ (21.5)	(47.0)	$ (34.4)	(58.6)	(81.4)
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-operating expenses	7.7		4.7		15.1	9.7
Tax benefit	(2.0)		(1.2)		(3.9)	(2.5)
Total reclassifications for the period, net of tax	5.7		3.5		11.2	7.2
Reclassification out of AOCI | Actuarial Losses Recognized
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Non-operating expenses	7.7		4.7		15.1	9.7
Tax benefit	(2.0)		(1.2)		(3.9)	(2.5)
Total reclassifications for the period, net of tax	$ 5.7		$ 3.5		$ 11.2	$ 7.2