RESTRUCTURING RESERVES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2016
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$ 79.2
Restructuring charges	21.5
Reduction of prior restructuring accruals	(2.3)
Cash payments and other adjustments	(14.3)
Balance, end of period	84.1
Current		$ 50.9
Non-current		33.2
Total Restructuring Reserve	79.2	84.1
LabCorp Diagnostics [Member] | Severance and Other Employee Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	0.1
Restructuring charges	3.2
Reduction of prior restructuring accruals	0.0
Cash payments and other adjustments	(2.0)
Balance, end of period	1.3
Total Restructuring Reserve	0.1	1.3
LabCorp Diagnostics [Member] | Lease and Other Facility Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	26.5
Restructuring charges	0.1
Reduction of prior restructuring accruals	(0.1)
Cash payments and other adjustments	(10.8)
Balance, end of period	15.7
Total Restructuring Reserve	26.5	15.7
Covance Drug Development [Member] | Severance and Other Employee Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	51.5
Restructuring charges	1.3
Reduction of prior restructuring accruals	2.2
Cash payments and other adjustments	(8.6)
Balance, end of period	42.0
Total Restructuring Reserve	51.5	42.0
Covance Drug Development [Member] | Lease and Other Facility Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	1.1
Restructuring charges	16.9
Reduction of prior restructuring accruals	0.0
Cash payments and other adjustments	(7.1)
Balance, end of period	25.1
Total Restructuring Reserve	$ 1.1	$ 25.1