ACCOUNTS RECEIVABLE, NET (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ (22.1)	$ (19.0)
Accounts receivable, net [Abstract]
Less allowance for doubtful accounts attributable to CDD		(12.7)
Accounts Receivable, after Allowance for Credit Loss, Current	2,479.8	1,543.9
LabCorp Diagnostics [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss	1,515.5	798.1
Covance Drug Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss	$ 986.4	$ 764.8