Business Acquisitions, Investments and Restructuring Charges - Acquisitions (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Purchase price:
Cash used in acquisitions, net of cash acquired	$ 455.9	$ 130.5
Excess purchase price allocated as follows:
Goodwill	11,650.5		$ 11,400.1
Series of Individually Immaterial Business Acquisitions
Purchase price:
Cash used in acquisitions, net of cash acquired	424.3	111.1
Contingent consideration	2.5	0.0
Holdbacks	16.0	10.9
Fair value, future minimum lease payments	5.8	0.0
Total	448.6	122.0
Allocated as follows:
Accounts receivable	18.3	1.9
Landfill airspace	0.0	22.2
Property and equipment	143.0	17.5
Operating right-of-use lease assets	18.1
Other assets	2.5	0.1
Inventory	1.1	0.2
Accounts payable	(11.5)	(0.3)
Environmental remediation liabilities	(0.1)	0.0
Closure and post-closure liabilities	0.0	(1.7)
Operating right-of-use lease liabilities	(18.4)
Other liabilities	(2.3)	(3.7)
Fair value of tangible assets acquired and liabilities assumed	150.7	36.2
Excess purchase price allocated as follows:
Other intangible assets	31.5	14.8
Goodwill	266.4	71.0
Total allocated	$ 297.9	$ 85.8