SIGNIFICANT ACCOUNTING POLICIES - Goodwill and Other Intangible Assets (Details) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($) item segment	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)
Changes in the carrying amount of goodwill for each of the company's reportable segments
Number of reporting units | item	10
Number of operating units | segment	10	10
Changes in the carrying amount of goodwill
Beginning goodwill		$ 8,012.7	$ 8,063.9
Prior year business combinations		0.7	253.8
Effect of foreign currency translation		65.4	(305.0)
Current year business combinations		70.1
Ending goodwill		8,148.2	8,012.7
Goodwill expected to be tax deductible		62.0
Impairment of goodwill		0.0	0.0
Nalco Holding Company ("Nalco") | Trademarks
Changes in the carrying amount of goodwill
Carrying value of asset subject to impairment testing	$ 1,200.0
Impairment of indefinite life intangible asset		0.0
Global Industrial
Changes in the carrying amount of goodwill
Beginning goodwill		4,081.8	4,270.1
Prior year business combinations			0.4
Effect of foreign currency translation		28.0	(188.7)
Current year business combinations		30.8
Ending goodwill		4,140.6	4,081.8
Global Institutional and Specialty
Changes in the carrying amount of goodwill
Beginning goodwill		567.6	576.5
Effect of foreign currency translation		3.1	(8.9)
Current year business combinations		39.3
Ending goodwill		610.0	567.6
Global Healthcare and Life Sciences
Changes in the carrying amount of goodwill
Beginning goodwill		3,125.4	2,974.2
Prior year business combinations			253.4
Effect of foreign currency translation		33.0	(102.2)
Ending goodwill		3,158.4	3,125.4
Other
Changes in the carrying amount of goodwill
Beginning goodwill		237.9	243.1
Effect of foreign currency translation		1.3	(5.2)
Ending goodwill		$ 239.2	$ 237.9