Share-Based Compensation (Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share based compensation expense	$ 14.3	$ 11.1	$ 56.2	$ 45.2
Tax benefit	(3.5)	(2.7)	(13.7)	(10.9)
After-tax expense	(10.8)	(8.4)	(42.5)	(34.3)
Stock Options [Member]
Share based compensation expense	2.2	2.1	14.0	12.3
Restricted Stock Units (RSUs) [Member]
Share based compensation expense	3.4	3.0	20.0	16.7
Phantom Share Units (PSUs) [Member]
Share based compensation expense	7.5	5.2	18.8	15.6
Deferred Compensation [Member]
Share based compensation expense	1.2	0.8	3.4	0.6
Continuing Operations [Member]
After-tax expense	(10.8)	(8.6)	(42.5)	(34.7)
Discontinued Operations [Member]
After-tax expense	$ 0.0	$ (0.2)	$ 0.0	$ (0.4)