GOODWILL AND INTANGIBLE ASSETS - SCHEDULE OF GOODWILL (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill	$ 3,099.4	$ 3,022.8
Adjustments to goodwill	(12.8)	(5.2)
Goodwill, Acquired During Period	3,141.1	81.8
Goodwill [Roll Forward]
Balance as of January 1	3,099.4	3,022.8
Adjustments to goodwill	(12.8)	(5.2)
Goodwill, net	6,227.7	3,099.4
LabCorp Diagnostics [Member]
Goodwill [Line Items]
Goodwill	2,988.9	2,912.3
Adjustments to goodwill	(12.8)	(5.2)
Goodwill, Acquired During Period	161.6	81.8
Goodwill [Roll Forward]
Balance as of January 1	2,988.9	2,912.3
Adjustments to goodwill	(12.8)	(5.2)
Goodwill, net	3,137.7	2,988.9
Covance Drug Development [Member]
Goodwill [Line Items]
Goodwill	110.5	110.5
Adjustments to goodwill	0.0	0.0
Goodwill, Acquired During Period	2,979.5	0.0
Goodwill [Roll Forward]
Balance as of January 1	110.5	110.5
Adjustments to goodwill	0.0	0.0
Goodwill, net	$ 3,090.0	$ 110.5