Stock-Based Compensation Plans (Schedule of Stock Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share -based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 9.8	$ 9.1	$ 19.7	$ 18.2
Total	71.2		71.2
Equity Option [Member]
Share -based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	8.6	8.5	17.1	17.0
Restricted Stock Units [Member]
Share -based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1.2	$ 0.6	$ 2.6	$ 1.2