Stock-Based Compensation (Nature Of Total Stock-Based Compensation) (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 Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 15.5	$ 16.3	$ 45.0	$ 44.2
Share-based Payment Arrangement, Expensed and Capitalized, Amount	15.8	16.7	45.8	45.4
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	13.4	12.3	35.9	33.2
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1.3	3.3	6.6	9.0
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 1.1	$ 1.1	$ 3.3	$ 3.2