BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 13,008.9	$ 12,161.6	$ 11,863.9
Depreciation	387.1	357.5	343.6
Operating Income (Loss)	1,086.7	725.6	1,436.5
Amortization of intangibles and other assets	(256.4)	(219.8)	(193.6)
Net restructuring charges	(46.0)	(49.1)	(54.0)
Goodwill and other asset impairments	5.3	349.0	261.7
Property, plant and equipment, net	3,045.4	2,911.8
Operating Segments
Segment Reporting Information [Line Items]
Operating Income (Loss)	2,065.2	1,987.6	2,414.6
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	58.0	27.7	36.9
LabCorp Diagnostics [Member]
Segment Reporting Information [Line Items]
Labor	4,438.7	4,095.7	3,659.6
Supplies	2,209.6	2,066.0	1,914.7
Other operating expenses	1,630.7	1,426.0	1,376.6
LabCorp Diagnostics [Member] | Operating Segments
Segment Reporting Information [Line Items]
Revenues	10,144.3	9,415.1	9,203.5
Depreciation	259.0	236.1	227.1
Operating Income (Loss)	1,606.3	1,591.3	2,025.5
Biopharma Laboratory Services
Segment Reporting Information [Line Items]
Labor	1,165.3	1,094.0	1,069.6
Supplies	441.9	452.2	460.6
Shipping costs	365.8	333.0	311.3
Other operating expenses	368.1	386.2	353.9
Biopharma Laboratory Services | Operating Segments
Segment Reporting Information [Line Items]
Revenues	2,922.6	2,774.2	2,697.3
Depreciation	122.6	112.5	112.8
Operating Income (Loss)	458.9	396.3	389.1
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Depreciation	5.5	8.9	3.7
Operating Income (Loss)	(670.8)	(644.1)	$ (468.8)
Other countries [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	113.8	98.9
North America
Segment Reporting Information [Line Items]
Property, plant and equipment, net	2,576.1	2,418.2
Europe [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 355.5	$ 394.7