Employee Benefit Plans (Supplemental Retirement Programs) (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits [Member]
Expenses associated with retirement programs	$ 1.8	$ 3.7	$ 6.6
Other liabilities	79.6	85.6
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Net periodic benefit costs	9.8	10.0	11.5
Benefit obligation	68.4	72.4
Supplemental Life Plan [Member]
Additional death benefits, minimum range	0.4
Additional death benefits, maximum range	$ 2.0