CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Common Stock, Value, Outstanding		$ 10.4
Additional Paid in Capital			$ 0.0
Retained Earnings (Accumulated Deficit)				$ 3,786.1
Treasury Stock, Value					$ (965.5)
Accumulated Other Comprehensive Income (Loss), Net of Tax						$ (10.5)
BALANCE at Dec. 31, 2014	$ 2,820.5
Net earnings attributable to Laboratory Corporation of America Holdings	437.6	0.0	0.0	437.6	0.0	0.0
Other comprehensive earnings, net of tax	(276.5)	0.0	0.0	0.0	0.0	(276.5)
Issuance of common stock for acquisition consideration	1,762.5	1.5	1,761.0	0.0	0.0	0.0
Issuance of common stock under employee stock plans	98.9	0.1	98.8	0.0	0.0	0.0
Surrender of restricted stock and performance share awards	(12.6)	0.0	0.0	0.0	(12.6)	0.0
Conversion of zero-coupon convertible debt	0.4	0.0	0.4	0.0	0.0	0.0
Stock compensation	102.1	0.0	102.1	0.0	0.0	0.0
Income tax benefit from stock options exercised	12.2	0.0	12.2	0.0	0.0	0.0
BALANCE at Dec. 31, 2015	4,945.1
Common Stock, Value, Outstanding	12.0	12.0
Additional Paid in Capital	1,974.5		1,974.5
Retained Earnings (Accumulated Deficit)	4,223.7			4,223.7
Treasury Stock, Value	(978.1)				(978.1)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(287.0)					(287.0)
Net earnings attributable to Laboratory Corporation of America Holdings	732.1	0.0	0.0	732.1	0.0	0.0
Other comprehensive earnings, net of tax	(294.1)	0.0	0.0	0.0	0.0	(294.1)
Issuance of common stock under employee stock plans	70.6	0.1	70.5	0.0	0.0	0.0
Surrender of restricted stock and performance share awards	(34.6)	0.0	0.0	0.0	(34.6)	0.0
Conversion of zero-coupon convertible debt	21.0	0.0	21.0	0.0	0.0	0.0
Stock compensation	109.6	0.0	109.6	0.0	0.0	0.0
Purchase of common stock	(43.9)	0.0	(43.9)	0.0	0.0	0.0
BALANCE at Dec. 31, 2016	5,505.8
Common Stock, Value, Outstanding	12.1	$ 12.1
Additional Paid in Capital	2,131.7		$ 2,131.7
Retained Earnings (Accumulated Deficit)	4,955.8			$ 4,955.8
Treasury Stock, Value	(1,012.7)				$ (1,012.7)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (581.1)					$ (581.1)