The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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GOODWILL AND OTHER INTANGIBLE ASSETS (Details) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($)	Jun. 30, 2018 item	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Changes in the carrying amount of goodwill
Beginning goodwill				$ 7,167.1
Current year business combinations				30.5
Dispositions				(2.9)
Effect of foreign currency translation				116.3
Ending goodwill	$ 7,078.4			7,078.4		$ 7,167.1
Number of operating units \| item		11
Impairment of goodwill				0.0		0.0
Future estimated amortization expense related to amortizable other identifiable intangible assets
Estimated expense remaining for the year	78.1			78.1
Total amortization expense related to other intangible assets	78.6		$ 77.6	238.9	$ 228.5
Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill				7,167.1
Ending goodwill						7,167.1
Nalco \| Trademarks
Changes in the carrying amount of goodwill
Carrying value of asset subject to impairment testing	1.2			1.2
Impairment of indefinite life intangible asset				0.0
Global Industrial
Changes in the carrying amount of goodwill
Beginning goodwill				2,725.3
Segment change						(71.7)
Current year business combinations				18.8
Effect of foreign currency translation				44.3
Ending goodwill	2,699.8			2,699.8		2,725.3
Global Industrial \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill				2,797.0
Ending goodwill						2,797.0
Global Institutional
Changes in the carrying amount of goodwill
Beginning goodwill				1,027.0
Current year business combinations				11.7
Effect of foreign currency translation				16.8
Ending goodwill	1,021.9			1,021.9		1,027.0
Global Institutional \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill				1,027.0
Ending goodwill						1,027.0
Global Energy
Changes in the carrying amount of goodwill
Beginning goodwill				3,203.7
Dispositions				(2.9)
Effect of foreign currency translation				51.8
Ending goodwill	3,149.0			3,149.0		3,203.7
Global Energy \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill				3,203.7
Ending goodwill						3,203.7
Other
Changes in the carrying amount of goodwill
Beginning goodwill				211.1
Segment change						71.7
Effect of foreign currency translation				3.4
Ending goodwill	$ 207.7			207.7		211.1
Other \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill				$ 139.4
Ending goodwill						$ 139.4