GOODWILL AND OTHER INTANGIBLE ASSETS (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($) item	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Changes in the carrying amount of goodwill for each of the company's reportable segments
Number of reporting units | item	11
Impairment of goodwill			$ 0.0
Changes in the carrying amount of goodwill
Beginning goodwill			5,569.1
Current year business combinations			272.7
Prior year business combinations			0.3
Dispositions			(47.6)
Effect of foreign currency translation			(34.6)
Ending goodwill	$ 5,759.9		5,759.9		$ 5,569.1
Goodwill expected to be tax deductible	0.0		0.0
Carrying value of asset subject to impairment testing	1,200.0		1,200.0
Future estimated amortization expense related to amortizable other identifiable intangible assets
Estimated expense remaining for the three-month period	109.0		109.0
Total amortization expense related to other intangible assets	50.8	$ 52.7	103.2	$ 103.5
Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill			5,569.1
Ending goodwill					5,569.1
Nalco | Trademarks
Changes in the carrying amount of goodwill
Impairment of indefinite life intangible asset			0.0
Global Industrial
Changes in the carrying amount of goodwill
Beginning goodwill			3,923.8
Segment changes					1,124.6
Current year business combinations			272.7
Dispositions			(47.6)
Effect of foreign currency translation			(32.4)
Ending goodwill	4,116.5		4,116.5		3,923.8
Global Industrial | Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill			2,799.2
Ending goodwill					2,799.2
Global Institutional
Changes in the carrying amount of goodwill
Beginning goodwill			548.3
Segment changes					(599.4)
Effect of foreign currency translation			(0.4)
Ending goodwill	547.9		547.9		548.3
Global Institutional | Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill			1,147.7
Ending goodwill					1,147.7
Global Healthcare and Life Sciences
Changes in the carrying amount of goodwill
Beginning goodwill			859.3
Segment changes					859.3
Prior year business combinations			0.3
Effect of foreign currency translation			(1.2)
Ending goodwill	858.4		858.4		859.3
Global Energy
Changes in the carrying amount of goodwill
Segment changes					(1,417.9)
Global Energy | Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill			1,417.9
Ending goodwill					1,417.9
Other
Changes in the carrying amount of goodwill
Beginning goodwill			237.7
Segment changes					33.4
Effect of foreign currency translation			(0.6)
Ending goodwill	$ 237.1		237.1		237.7
Other | Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill			$ 204.3
Ending goodwill					$ 204.3