Landfill and Environmental Costs - Final Capping, Closure and Post-Closure Costs (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
| Activity in asset retirement obligation liabilities, which includes liabilities for final capping, closure and post-closure | ||||
| Asset retirement obligation liabilities, beginning of year | $ 1,257.7 | $ 1,224.6 | ||
| Non-cash additions | 21.8 | 22.3 | ||
| Acquisitions, net of divestitures and other adjustments | 1.9 | (25.1) | ||
| Asset retirement obligation adjustments | (17.6) | 0.1 | ||
| Payments | (22.1) | (28.3) | ||
| Accretion expense | $ 20.2 | $ 19.9 | 40.6 | 39.9 |
| Asset retirement obligation liabilities, end of period | 1,282.3 | 1,233.5 | 1,282.3 | 1,233.5 |
| Less: current portion | (81.0) | (71.7) | (81.0) | (71.7) |
| Long-term portion | $ 1,201.3 | $ 1,161.8 | $ 1,201.3 | $ 1,161.8 |