BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 2,956.2	$ 2,815.4
Depreciation and amortization:
Depreciation and amortization	374.6	375.6	$ 349.3
Revenues	14,876.8	16,120.9	13,978.5
Operating Income (Loss)	1,773.9	3,259.5	2,445.4
Amortization of intangibles and other assets	(259.3)	(369.6)	(275.4)
Net restructuring charges	(83.8)	(43.1)	(40.6)
Goodwill and Intangible Asset Impairment	(271.5)	0.0	(462.1)
Total pre-tax income	1,582.6	3,126.6	2,219.1
Provision for income taxes	302.0	747.1	662.1
Net earnings	1,280.6	2,379.5	1,557.0
Net Income (Loss) Attributable to Noncontrolling Interest	(1.5)	(2.2)	(0.9)
Net earnings attributable to Laboratory Corporation of America Holdings	1,279.1	2,377.3	1,556.1
Operating Segments
Depreciation and amortization:
Operating Income (Loss)	2,826.6	4,092.7	3,522.9
Intersegment Eliminations
Depreciation and amortization:
Revenues	36.9	88.2	152.6
LabCorp Diagnostics [Member]
Depreciation and amortization:
Goodwill and Intangible Asset Impairment			(11.6)
LabCorp Diagnostics [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	1,669.2	1,507.3
Depreciation and amortization:
Depreciation and amortization	227.1	238.7	222.6
Revenues	9,203.5	10,363.6	9,253.4
Operating Income (Loss)	2,025.5	3,205.6	2,801.3
Covance Drug Development [Member]
Depreciation and amortization:
Goodwill and Intangible Asset Impairment			(450.5)
Covance Drug Development [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	1,287.0	1,308.1
Depreciation and amortization:
Depreciation and amortization	143.8	134.3	124.7
Revenues	5,710.2	5,845.5	4,877.7
Operating Income (Loss)	801.1	887.1	721.6
Corporate Segment [Member]
Depreciation and amortization:
Depreciation and amortization	3.7	2.6	2.0
Operating Income (Loss)	(438.1)	(420.5)	$ (299.4)
Other countries [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	131.5	188.0
Other countries [Member] | LabCorp Diagnostics [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	0.0	0.0
Other countries [Member] | Covance Drug Development [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	131.5	188.0
North America
Segment Reporting Information [Line Items]
Property, plant and equipment, net	2,399.2	2,177.5
North America | LabCorp Diagnostics [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	1,669.2	1,507.3
North America | Covance Drug Development [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	730.0	670.2
Europe [Member]
Segment Reporting Information [Line Items]
Property, plant and equipment, net	425.5	449.9
Europe [Member] | LabCorp Diagnostics [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	0.0	0.0
Europe [Member] | Covance Drug Development [Member] | Operating Segments
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 425.5	$ 449.9