GOODWILL AND OTHER INTANGIBLE ASSETS (Details) $ in Millions	3 Months Ended				12 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2024 USD ($) segment	Mar. 31, 2024 USD ($) item	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Changes in the carrying amount of goodwill for each of the company's reportable segments
Impairment of goodwill	$ 0.0
Changes in the carrying amount of goodwill
Beginning goodwill	8,148.2
Goodwill revised					$ 8,148.2
Effect of foreign currency translation	(36.8)
Ending goodwill	8,111.4				8,148.2
Number of operating units		8	8
Future estimated amortization expense related to amortizable other identifiable intangible assets
Estimated expense for the remaining six-month period	224.0	$ 224.0	$ 224.0
Total amortization expense related to other intangible assets	77.8			$ 75.6
Nalco Holding Company ("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	4,140.6
Segment changes					102.9
Goodwill revised					4,243.5
Effect of foreign currency translation	(26.0)
Ending goodwill	4,217.5				4,140.6
Global Institutional and Specialty
Changes in the carrying amount of goodwill
Beginning goodwill	610.0
Goodwill revised					610.0
Effect of foreign currency translation	(0.8)
Ending goodwill	609.2				610.0
Global Healthcare and Life Sciences
Changes in the carrying amount of goodwill
Beginning goodwill	3,158.4
Goodwill revised					3,158.4
Effect of foreign currency translation	(9.8)
Ending goodwill	3,148.6				3,158.4
Global Pest Elimination
Changes in the carrying amount of goodwill
Segment changes					136.3
Goodwill revised					136.3
Effect of foreign currency translation	(0.2)
Ending goodwill	136.1
Other
Changes in the carrying amount of goodwill
Beginning goodwill	$ 239.2
Segment changes					(239.2)
Ending goodwill					$ 239.2