Stock-Based Compensation Plans (Schedule Of Stock Based Compensation Expense) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 39.1	$ 36.5	$ 24.8
Equity Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		33.5	33.8	33.7
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ (3.0)	5.6	2.7	(1.1)
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ (8.5)	$ 0.0	$ 0.0	$ (7.8)