Principles Of Consolidation (Estimated Cash Payments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Workers' Compensation [Member]
Liability for Unpaid Claims and Claims Adjustment Expense, Adjustment of Opening Balance [Line Items]
2013	$ 84.1
2014	58.5
2015	42.5
2016	33.0
2017	25.7
Thereafter	146.3
Total	390.1
Property Damage and Liability Claims [Member]
Liability for Unpaid Claims and Claims Adjustment Expense, Adjustment of Opening Balance [Line Items]
2013	22.4
2014	17.3
2015	12.4
2016	6.8
2017	3.4
Thereafter	2.8
Total	65.1
Total [Member]
Liability for Unpaid Claims and Claims Adjustment Expense, Adjustment of Opening Balance [Line Items]
2013	106.5
2014	75.8
2015	54.9
2016	39.8
2017	29.1
Thereafter	149.1
Total	$ 455.2