GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 259,300,000	$ 369,600,000	$ 275,400,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Asset	68,300,000	9,100,000
Finite-Lived Intangible Assets, Future Amortization Expense
Estimated amortization expense, 2013	273,500,000
Estimated amortization expense, 2014	268,900,000
Estimated amortization expense, 2015	256,700,000
Estimated amortization expense, 2016	246,900,000
Estimated amortization expense, 2017	232,500,000
Estimated amortization expense, Thereafter	2,055,600,000
Goodwill, Impairment Loss	260,000,000.0	0
Goodwill and Intangible Asset Impairment	271,500,000	0	462,100,000
Goodwill Impairment, Cumulative	733,600,000
Covance Drug Development [Member]
Finite-Lived Intangible Assets, Future Amortization Expense
Goodwill, Impairment Loss	260,000,000.0	0	418,700,000
Impairment of Intangible Assets (Excluding Goodwill)		31,800,000
Goodwill and Intangible Asset Impairment			450,500,000
Covance Drug Development [Member] | Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets, Future Amortization Expense
Amortization	88.4	27,500,000
LabCorp Diagnostics [Member]
Finite-Lived Intangible Assets, Future Amortization Expense
Goodwill, Impairment Loss	$ 0	0	3,700,000
Impairment of Intangible Assets (Excluding Goodwill)		$ 7,900,000
Goodwill and Intangible Asset Impairment			$ 11,600,000