Share-Based Compensation (Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	$ 6.0	$ 5.9	$ 22.1	$ 20.3
Tax benefit	(0.6)	(0.6)	(2.2)	(2.5)
After-tax expense	5.4	5.3	19.9	17.8
Stock options
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	0.9	0.8	4.0	3.6
Restricted Stock Units (RSUs)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	3.1	3.1	12.1	11.2
Performance Share Units (PSUs)
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense (benefit)	$ 2.0	$ 2.0	$ 6.0	$ 5.5