Share-Based Compensation And Capital Stock Pre-Tax Stock-Based Compensation Expenses And Associated Income Tax Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allocated Share-based Compensation Expense	$ 11.2	$ 8.9	$ 9.0
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	4.1	3.3	3.4
Stock Options
Allocated Share-based Compensation Expense	2.8	2.4	2.8
Restricted Stock [Member]
Allocated Share-based Compensation Expense	7.7	6.8	6.4
Performance Vested Restricted Stock Units
Allocated Share-based Compensation Expense	0.7	(0.3)	(0.2)
Scenario, Adjustment [Member] | Performance Vested Restricted Stock Units
Allocated Share-based Compensation Expense	0.1	(0.8)	(0.9)
Acceleration Of Award Vesting Conditions [Member] | Stock Options
Allocated Share-based Compensation Expense	0.2		0.5
Acceleration Of Award Vesting Conditions [Member] | Restricted Stock [Member]
Allocated Share-based Compensation Expense	$ 0.5		$ 0.2