BUSINESS SEGMENT INFORMATION Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Percent of Revenue Contributed	100.00%	100.00%	100.00%	100.00%
Intercompany revenue elimination	$ (7.3)	$ (14.4)	$ (31.5)	$ (68.9)
Revenues	3,606.1	4,062.6	11,202.6	12,064.8
Operating Income (Loss)	469.4	766.9	1,683.2	2,528.9
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (66.0)	$ (97.4)	$ (206.1)	$ (191.8)
LabCorp Diagnostics [Member]
Segment Reporting Information [Line Items]
Percent of Revenue Contributed	61.00%	64.00%	61.00%	64.00%
Revenues	$ 2,207.6	$ 2,617.5	$ 6,917.1	$ 7,740.8
Operating Income (Loss)	378.7	722.7	1,457.5	2,275.4
Covance Drug Development [Member]
Segment Reporting Information [Line Items]
Revenues	1,405.8	1,459.5	4,317.0	4,392.9
Operating Income (Loss)	$ 156.7	$ 141.6	$ 431.8	$ 445.3