Landfill and Environmental Costs (Environmental Remediation Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Activity in environmental remediation liabilities
Environmental remediation liabilities, beginning of year	$ 500.2	$ 540.2	$ 564.0
Net additions charged to expense	5.1	(12.5)	5.0
Payments	(63.5)	(49.1)	(48.8)
Accrual For Environmental Loss Contingencies Accretion Expense	18.6	19.0	20.2
Acquisitions, net of divestitures and other adjustments	2.4	2.6	(0.2)
Environmental remediation liabilities, end of year	462.8	500.2	540.2
Less: current portion	(57.0)	(56.8)	(53.9)
Long-term portion	$ 405.8	$ 443.4	$ 486.3