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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The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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GOODWILL AND OTHER INTANGIBLE ASSETS (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) item	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Changes in the carrying amount of goodwill
Beginning goodwill, net			$ 6,383.0
Current year business combinations			510.6
Prior year business combinations			0.3
Effect of foreign currency translation			(260.5)
Ending goodwill, net	$ 7,154.4		7,154.4		$ 6,383.0
Goodwill expected to be tax deductible	4.1		$ 4.1
Number of operating units \| item			11
Impairment of goodwill			$ 0.0
Future estimated amortization expense related to amortizable other identifiable intangible assets
Estimated expense remaining for the year	84.0		84.0
Total amortization expense related to other intangible assets	77.6	$ 71.9	228.5	$ 217.2
Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill, net			6,383.0
Ending goodwill, net					6,383.0
Nalco \| Trademarks
Changes in the carrying amount of goodwill
Carrying value of asset subject to impairment testing	1,200.0		1,200.0
Impairment of indefinite life intangible asset			0.0
Global Industrial
Changes in the carrying amount of goodwill
Beginning goodwill, net			2,585.0
Current year business combinations			4.1
Effect of foreign currency translation			(97.9)
Ending goodwill, net	2,687.0		2,687.0		2,585.0
Global Industrial \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill, net			2,522.3
Ending goodwill, net					2,522.3
Global Industrial \| Adjustment.
Changes in the carrying amount of goodwill
Reclassifications					62.7
Global Institutional
Changes in the carrying amount of goodwill
Beginning goodwill, net			590.7
Current year business combinations			506.5
Effect of foreign currency translation			(41.6)
Ending goodwill, net	1,138.8		1,138.8		590.7
Global Institutional \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill, net			653.4
Ending goodwill, net					653.4
Global Institutional \| Adjustment.
Changes in the carrying amount of goodwill
Reclassifications					(62.7)
Global Energy
Changes in the carrying amount of goodwill
Beginning goodwill, net			3,093.6
Prior year business combinations			0.3
Effect of foreign currency translation			(116.8)
Ending goodwill, net	3,210.7		3,210.7		3,093.6
Global Energy \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill, net			3,093.6
Ending goodwill, net					3,093.6
Other
Changes in the carrying amount of goodwill
Beginning goodwill, net			113.7
Effect of foreign currency translation			(4.2)
Ending goodwill, net	$ 117.9		117.9		113.7
Other \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill, net			$ 113.7
Ending goodwill, net					$ 113.7