QUARTERLY DATA (UNAUDITED) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly data summary:

The following is a summary of unaudited quarterly data:

	Year Ended December 31, 2017
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter (a)		Full Year
Net revenues	$	2,408.1	$	2,498.4	$	2,597.9	$	2,701.5	$	10,205.9
Gross profit	803.6		861.8		882.8		915.8		3,464.0
Net earnings attributable to Laboratory Corporation of America Holdings	192.2		188.6		180.6		706.8		1,268.2
Basic earnings per common share	1.87		1.84		1.77		6.91		12.39
Diluted earnings per common share	1.84		1.82		1.74		6.81		12.21

(a) Net earnings attributable to Laboratory Corporation of America Holdings in the fourth quarter of 2017 includes amounts recorded due to TCJA.

	Year Ended December 31, 2016
	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter		Full Year
Net revenues	$	2,295.2	$	2,382.0	$	2,372.7	$	2,387.3	$	9,437.2
Gross profit	777.3		826.8		788.4		788.0		3,180.5
Net earnings attributable to Laboratory Corporation of America Holdings	164.1		204.1		179.5		184.4		732.1
Basic earnings per common share	1.61		2.00		1.74		1.79		7.14
Diluted earnings per common share	1.58		1.96		1.71		1.75		7.02