BUSINESS SEGMENT INFORMATION Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Percent of Revenue Contributed	100.00%	100.00%	100.00%	100.00%
Intercompany revenue elimination	$ (10.4)	$ (20.0)	$ (24.2)	$ (54.5)
Revenues	3,696.9	3,840.7	7,596.5	8,002.2
Operating Income (Loss)	525.9	704.1	1,213.8	1,762.0
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (80.5)	$ (46.8)	$ (140.1)	$ (94.4)
LabCorp Diagnostics [Member]
Segment Reporting Information [Line Items]
Percent of Revenue Contributed	61.00%	61.00%	62.00%	63.00%
Revenues	$ 2,255.4	$ 2,365.5	$ 4,709.5	$ 5,123.3
Operating Income (Loss)	455.5	603.6	1,078.8	1,552.7
Covance Drug Development [Member]
Segment Reporting Information [Line Items]
Revenues	1,451.9	1,495.2	2,911.2	2,933.4
Operating Income (Loss)	$ 150.9	$ 147.3	$ 275.1	$ 303.7