GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 5,149.7		$ 5,149.7		$ 5,058.4
Goodwill	6,220.2		6,220.2		6,142.5
Amortization of intangibles and other assets	62.2	$ 51.5	122.3	$ 104.9
Adjustments to goodwill			(64.0)
Estimated amortization expense, 2013	237.2		237.2
Estimated amortization expense, 2014	228.2		228.2
Estimated amortization expense, 2015	216.9		216.9
Estimated amortization expense, 2016	209.1		209.1
Estimated amortization expense, Thereafter	1,735.8		1,735.8
Current Expected Credit Losses Opening Balance Sheet Impact on Retained Earnings			3.4
Amortization of intangible assets	62.2	$ 51.5	122.3	$ 104.9
LabCorp Diagnostics [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	4,944.9		4,944.9		4,813.9
Adjustments to goodwill			(10.7)
Covance Drug Development [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,275.3		1,275.3		$ 1,328.6
Adjustments to goodwill			$ (53.3)