GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF GOODWILL (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Goodwill	$ 6,369.7	$ 6,142.5	$ 6,123.7
Adjustments to goodwill	(72.7)	55.5
Goodwill, Acquired During Period	299.9	296.9	598.5
Goodwill, Impairment Loss	0.0	(333.6)
Net Carrying Amount	3,488.9	3,342.0
Goodwill Impairment, Cumulative	648.5
Goodwill Impairment, Remaining Goodwill for ED Reporting Unit	0.0
Gross Carrying Amount	5,433.3	5,058.4
Accumulated Amortization	(1,944.4)	(1,716.4)
Goodwill [Roll Forward]
Balance as of January 1	6,142.5	6,123.7
Adjustments to goodwill	(72.7)	55.5
Goodwill, net	6,369.7	6,142.5	6,123.7
Goodwill and other asset impairments	5.3	349.0	261.7
Customer Relationships [Member]
Goodwill [Line Items]
Net Carrying Amount	2,574.0
Gross Carrying Amount	4,114.7
Accumulated Amortization	(1,540.7)
Patents, Licenses And Technology [Member]
Goodwill [Line Items]
Net Carrying Amount	348.6
Gross Carrying Amount	646.9
Accumulated Amortization	(298.3)
Non-compete agreements [Member]
Goodwill [Line Items]
Net Carrying Amount	96.3
Gross Carrying Amount	180.2
Accumulated Amortization	(83.9)
In Process R&A and Media
Goodwill [Line Items]
Net Carrying Amount	18.4	18.6
Gross Carrying Amount	39.9	34.1
Accumulated Amortization	(21.5)	(15.5)
Licensing Agreements [Member]
Goodwill [Line Items]
Net Carrying Amount	451.6
Gross Carrying Amount	451.6
Accumulated Amortization	0.0
Patents, Licenses And Technology [Member]
Goodwill [Line Items]
Net Carrying Amount		253.3
Gross Carrying Amount		526.6
Accumulated Amortization		(273.3)
Customer Relationships [Member]
Goodwill [Line Items]
Net Carrying Amount		2,501.4
Gross Carrying Amount		3,868.6
Accumulated Amortization		(1,367.2)
Non-compete agreements [Member]
Goodwill [Line Items]
Net Carrying Amount		69.9
Gross Carrying Amount		130.3
Accumulated Amortization		(60.4)
Licensing Agreements [Member]
Goodwill [Line Items]
Net Carrying Amount		498.8
Gross Carrying Amount		498.8
Accumulated Amortization		0.0
LabCorp Diagnostics [Member]
Goodwill [Line Items]
Goodwill	5,102.5	4,813.9	4,533.5
Adjustments to goodwill	(11.3)	(16.5)
Goodwill, Acquired During Period	299.9	296.9
Goodwill, Impairment Loss	0.0	0.0
Goodwill [Roll Forward]
Balance as of January 1	4,813.9	4,533.5
Adjustments to goodwill	(11.3)	(16.5)
Goodwill, net	5,102.5	4,813.9	4,533.5
Biopharma Laboratory Services
Goodwill [Line Items]
Goodwill	1,267.2	1,328.6	1,590.2
Adjustments to goodwill	(61.4)	72.0
Goodwill, Acquired During Period	0.0	0.0
Goodwill, Impairment Loss	0.0	(333.6)
Goodwill and other asset impairments		333.6
Goodwill [Roll Forward]
Balance as of January 1	1,328.6	1,590.2
Adjustments to goodwill	(61.4)	72.0
Goodwill, net	$ 1,267.2	$ 1,328.6	$ 1,590.2