ACCOUNTS RECEIVABLE, NET (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ (19.0)	$ (15.7)
Accounts receivable, net [Abstract]
Less allowance for doubtful accounts attributable to CDD	(328.0)	(306.2)
Accounts receivable, net	1,543.9	1,467.9
LabCorp Diagnostics [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss	798.1	793.3
Covance Drug Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss	$ 764.8	$ 690.3