Accounting Policies - Schedule of Estimated Cash Payments to Settle Claims (Details) $ in Millions	Dec. 31, 2019 USD ($)
Liability for Claims and Claims Adjustment Expense [Line Items]
2020	$ 111.8
2021	68.0
2022	44.7
2023	27.8
2024	19.0
Thereafter	88.1
Total	359.4
Workers’ Compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
2020	78.3
2021	50.1
2022	33.3
2023	22.0
2024	16.4
Thereafter	85.5
Total	285.6
Third-Party Liability Claims
Liability for Claims and Claims Adjustment Expense [Line Items]
2020	33.5
2021	17.9
2022	11.4
2023	5.8
2024	2.6
Thereafter	2.6
Total	$ 73.8