Stock-Based Compensation Plans (Schedule Of Future Share-Based Compensation Cost) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
2017	$ 10.1
2018	5.9
2019	3.3
2020	1.4
2021	0.9
Thereafter	1.7
Total	23.3
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
2017	2.1
2018	1.4
2019	1.1
2020	0.9
2021	0.8
Thereafter	1.7
Total	8.0
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
2017	8.0
2018	4.5
2019	2.2
2020	0.5
2021	0.1
Thereafter	0.0
Total	$ 15.3