CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) (USD $) In Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]
BALANCE at Dec. 31, 2012	$ 2,717.4	$ 11.3	$ 0	$ 3,588.5	$ (951.8)	$ 69.4
Net earnings attributable to Laboratory Corporation of America Holdings	147.2			147.2
Other comprehensive earnings, net of tax	(15.6)					(15.6)
Issuance of common stock under employee stock plans	28.8	0	28.8
Surrender of restricted stock and performance share awards	(2.4)				(2.4)
Stock compensation	11.3		11.3
Income tax benefit from stock options exercised	2.4		2.4
Purchase of common stock	(113.9)	(0.1)	(45.6)	(68.2)
BALANCE at Mar. 31, 2013	2,778.3	11.2	0	3,667.5	(954.2)	53.8
BALANCE at Dec. 31, 2013	2,491.3	10.5	0	3,373.5	(958.9)	66.2
Net earnings attributable to Laboratory Corporation of America Holdings	113.1			113.1
Other comprehensive earnings, net of tax	(20.7)					(20.7)
Issuance of common stock under employee stock plans	16.4	0	16.4
Surrender of restricted stock and performance share awards	(4.6)				(4.6)
Conversion of zero-coupon convertible debt	1.2
Stock compensation	11.7		11.7
Income tax benefit from stock options exercised	0.6		0.6
Purchase of common stock	(107.7)	(0.1)	(29.9)	(77.7)
BALANCE at Mar. 31, 2014	$ 2,501.3	$ 10.4	$ 0	$ 3,408.9	$ (963.5)	$ 45.5