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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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized after the fifth 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 of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next 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 of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third 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 of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second 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 INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 7,815.3		$ 7,815.3		$ 7,360.3
Amortization of intangible assets	61.7	$ 54.7	179.0	$ 175.5
Finite-Lived Intangible Assets, Future Amortization Expense
Estimated amortization expense, 2012	54.1		54.1
Estimated amortization expense, 2013	237.9		237.9
Estimated amortization expense, 2014	231.1		231.1
Estimated amortization expense, 2015	225.1		225.1
Estimated amortization expense, 2016	221.4		221.4
Estimated amortization expense, Thereafter	2,580.3		2,580.3
LabCorp Diagnostics [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	3,712.5		3,712.5		3,638.8
Covance Drug Development [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 4,102.8		$ 4,102.8		$ 3,721.5