Share-Based Compensation and Capital Stock Pre-Tax Stock-Based Compensation Expenses And Associated Income Tax Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	$ 1.8	$ 2.9	$ 4.8	$ 5.8
Income tax benefits	0.7	1.1	1.8	2.1
Stock Options [Member]
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	0.7	0.5	1.1	1.0
Restricted Stock [Member]
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	1.9	1.8	3.8	3.6
Performance Vested Restricted Stock Units [Member]
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	$ (0.8)	$ 0.6	$ (0.1)	$ 1.2