Accounting Policies (Estimated Cash Payments) (Details) $ in Millions	Dec. 31, 2018 USD ($)
Workers’ Compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
2019	$ 76.4
2020	48.8
2021	33.0
2022	22.4
2023	17.5
Thereafter	89.7
Total	287.8
Property Damage and Liability Claims
Liability for Claims and Claims Adjustment Expense [Line Items]
2019	27.6
2020	20.4
2021	13.2
2022	7.0
2023	3.1
Thereafter	2.3
Total	73.6
Total
Liability for Claims and Claims Adjustment Expense [Line Items]
2019	104.0
2020	69.2
2021	46.2
2022	29.4
2023	20.6
Thereafter	92.0
Total	$ 361.4