GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 4,738.5		$ 4,738.5		$ 4,593.2
Goodwill	6,182.2		6,182.2		6,123.7
Amortization of intangibles and other assets	51.5	$ 49.8	104.9	$ 100.0
Adjustments to goodwill			7.7
Estimated amortization expense, 2012	107.6		107.6
Estimated amortization expense, 2013	210.8		210.8
Estimated amortization expense, 2014	201.4		201.4
Estimated amortization expense, 2015	192.5		192.5
Estimated amortization expense, 2016	181.1		181.1
Estimated amortization expense, Thereafter	1,675.4		1,675.4
Current Expected Credit Losses Opening Balance Sheet Impact on Retained Earnings			4.3
Amortization of intangible assets	51.5	$ 49.8	104.9	$ 100.0
LabCorp Diagnostics [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	4,568.0		4,568.0		4,533.5
Adjustments to goodwill			(16.3)
Covance Drug Development [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,614.2		1,614.2		$ 1,590.2
Adjustments to goodwill			$ 24.0