Business Acquisitions, Investments and Restructuring Charges - Acquisitions (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Purchase price:
Cash used in acquisitions, net of cash acquired	$ 189.9	$ 455.9
Excess purchase price allocated as follows:
Goodwill	11,712.1		$ 11,633.4
Series of Individually Immaterial Business Acquisitions
Purchase price:
Cash used in acquisitions, net of cash acquired	133.8	424.3
Contingent consideration	0.0	2.5
Holdbacks	7.5	16.0
Fair value, future minimum finance lease payments	0.3	5.8
Total	141.6	448.6
Allocated as follows:
Accounts receivable	4.7	18.3
Property and equipment	36.9	143.0
Operating right-of-use lease assets	0.2	18.1
Other assets	0.2	2.5
Inventory	0.0	1.1
Accounts payable	(1.2)	(11.5)
Environmental remediation liabilities	(1.7)	(0.1)
Closure and post-closure liabilities	(0.7)	0.0
Operating right-of-use lease liabilities	(0.2)	(18.4)
Other liabilities	(2.1)	(2.3)
Fair value of tangible assets acquired and liabilities assumed	36.1	150.7
Excess purchase price allocated as follows:
Other intangible assets	9.8	31.5
Goodwill	95.7	266.4
Total allocated	$ 105.5	$ 297.9