BASIS OF FINANCIAL STATEMENT PRESENTATION (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Long-term Debt, Excluding Current Maturities	$ 5,473.2				$ 5,473.2		$ 5,940.3
Prior Period Reclassification Adjustment						$ 25.6
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 3.6				$ 13.4
Proceeds and Excess Tax Benefit from Share-based Compensation				$ 10.5
Share-based Compensation Arrangement by Share-based Payment Award, Options, Other Increases (Decreases) in Period		0.3	0.2
Ownership percentage below which investments are generally accounted for on the cost method (in thousandths)	20.00%
LabCorp Diagnostics [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Revenue Contributed	70.50%				69.80%
Covance Drug Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Revenue Contributed	29.50%					30.20%
Senior notes due 2018 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Long-term Debt, Excluding Current Maturities	$ 130.0				$ 130.0		$ 0.0