Business Acquisitions, Investments and Restructuring Charges (Acquisitions) (Details) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($) center state	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Purchase price:
Cash used in acquisitions, net of cash acquired				$ 277.3	$ 351.8	$ 62.4
Other intangible assets
Goodwill	$ 11,400.1	$ 11,315.4		11,400.1	11,315.4	$ 11,163.2
Nondeductible goodwill					42.2
ReCommunity Holdings II, Inc.
Other intangible assets
Number of centers | center			26
Number of states of operation | state			14
Group 1 | Hauling Operations
Other intangible assets
Fair value of divestiture	79.0		$ 70.0	79.0
Gain on divestiture	39.5		17.1
Waste Business Acquisitions
Purchase price:
Cash used in acquisitions, net of cash acquired				99.9	325.4
Contingent consideration				0.0	5.2
Holdbacks				11.2	7.7
Fair value, future minimum lease payments				0.0	6.0
Fair value of operations surrendered				78.6	70.1
Total				189.7	414.4
Allocated as follows:
Restricted cash	0.0	2.9		0.0	2.9
Accounts receivable	6.4	28.5		6.4	28.5
Landfill airspace	22.2	28.0		22.2	28.0
Property and equipment	28.0	130.7		28.0	130.7
Other assets	0.1	51.3		0.1	51.3
Inventory	0.2	4.3		0.2	4.3
Accounts payable	(0.3)	(6.5)		(0.3)	(6.5)
Environmental remediation liabilities	0.0	(0.8)		0.0	(0.8)
Closure and post-closure liabilities	(1.5)	(5.4)		(1.5)	(5.4)
Other liabilities	(6.1)	(25.0)		(6.1)	(25.0)
Fair value of tangible assets acquired and liabilities assumed	49.0	208.0		49.0	208.0
Excess purchase price to be allocated	140.7	206.4		140.7	206.4
Other intangible assets
Other intangible assets	27.8	25.5		27.8	25.5
Goodwill	112.9	180.9		112.9	180.9
Total allocated	140.7	206.4		140.7	206.4
Hauling, Recycling and Landfill Operations
Allocated as follows:
Property and equipment	10.3		35.2	10.3
Other intangible assets
Other intangible assets	12.4		8.8	12.4
Goodwill	$ 41.8		$ 26.1	$ 41.8
ReCommunity Holdings II, Inc.
Purchase price:
Cash used in acquisitions, net of cash acquired		167.1
Allocated as follows:
Property and equipment		50.0			50.0
Other intangible assets
Other intangible assets		3.5			3.5
Goodwill		69.1			69.1
Capital leases acquired		5.3			5.3
Deferred tax assets		$ 48.5			$ 48.5