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) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Changes in the carrying amount of goodwill
Beginning goodwill	$ 7,167.1
Current year business combinations	32.5
Prior year business combinations	0.1
Dispositions	(2.5)
Effect of foreign currency translation	(105.8)
Ending goodwill	7,303.0		$ 7,167.1
Impairment of goodwill	0.0		0.0
Future estimated amortization expense related to amortizable other identifiable intangible assets
Estimated expense remaining for the year	242.0
Total amortization expense related to other intangible assets	80.2	$ 73.8
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
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	20.7
Effect of foreign currency translation	(40.3)
Ending goodwill	2,786.3		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	11.8
Effect of foreign currency translation	(15.3)
Ending goodwill	1,054.1		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	(2.5)
Effect of foreign currency translation	(47.1)
Ending goodwill	3,248.3		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
Prior year business combinations	0.1
Effect of foreign currency translation	(3.1)
Ending goodwill	214.3		211.1
Other \| Previously Reported
Changes in the carrying amount of goodwill
Beginning goodwill	$ 139.4
Ending goodwill			$ 139.4