GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Beginning Balance			$ 3,604.0	$ 3,591.0
Goodwill acquired during year			32.2	46.5
Purchase accounting adjustments			(17.6)	(7.4)
Impairments during the year	$ (358.7)	$ (65.0)	(358.7)	(65.0)
Impairments related to disposition and held for sale (see Note 4)			(5.8)	(7.1)
Changes due to foreign currency fluctuations			(31.9)	46.0
Ending Balance	3,222.2	3,604.0	3,222.2	3,604.0
Domestic and Canada RCS
Goodwill [Roll Forward]
Beginning Balance			2,850.2	2,811.8
Goodwill acquired during year			32.2	36.9
Purchase accounting adjustments			(16.9)	(10.1)
Impairments related to disposition and held for sale (see Note 4)			(5.8)
Changes due to foreign currency fluctuations			(11.3)	11.6
Ending Balance	2,848.4	2,850.2	2,848.4	2,850.2
International Regulated Waste And Compliance Services
Goodwill [Roll Forward]
Beginning Balance			466.8	498.4
Goodwill acquired during year				4.9
Purchase accounting adjustments				1.2
Impairments during the year			(72.4)	(65.0)
Impairments related to disposition and held for sale (see Note 4)				(7.1)
Changes due to foreign currency fluctuations			(20.6)	34.4
Ending Balance	$ 373.8	466.8	373.8	466.8
All Other
Goodwill [Roll Forward]
Beginning Balance			287.0	280.8
Goodwill acquired during year				4.7
Purchase accounting adjustments			(0.7)	1.5
Impairments during the year			$ (286.3)
Ending Balance		$ 287.0		$ 287.0