Business Acquisitions and Restructuring Charges - Acquisitions (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Purchase price:
Cash used in acquisitions, net of cash acquired	$ 13.9	$ 512.6
Excess purchase price allocated as follows:
Goodwill	11,154.2		$ 11,145.5
Waste Business Acquisitions [Member]
Purchase price:
Cash used in acquisitions, net of cash acquired	13.9	512.6
Contingent consideration	0.0	75.8
Holdbacks	1.0	2.5
Fair value, future minimum lease payments	0.0	1.5
Total	14.9	592.4
Allocated as follows:
Accounts receivable	0.1	36.2
Landfill airspace	0.0	152.7
Property and equipment	4.4	150.0
Other assets	0.1	1.4
Accounts payable	0.0	(7.1)
Environmental remediation liabilities	(0.1)	(2.8)
Closure and post-closure liabilities	(0.1)	(11.3)
Other liabilities	(0.1)	(9.6)
Fair value of tangible assets acquired and liabilities assumed	4.3	309.5
Excess purchase price allocated as follows:
Other intangible assets	1.7	7.5
Goodwill	8.9	275.4
Total allocated	$ 10.6	$ 282.9