CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Statement [Abstract]
Net sales	$ 1,440.9	$ 1,423.3
Cost of sales	868.7	847.2
Gross profit	572.2	576.1
Selling, general and administrative expenses	283.2	271.2
Amortization of intangibles and other assets	19.5	21.4
Restructuring and other special charges	7.5	(3.6)
Operating income	262.0	287.1
Other income (expenses):
Interest expense	(24.5)	(21.5)
Equity method income, net	4.3	4.3
Investment income	0.2	0.2
Other, net	(0.6)	(0.5)
Earnings before income taxes	241.4	269.6
Provision for income taxes	93.8	107.6
Net earnings	147.6	162.0
Less: Net earnings attributable to the noncontrolling interest	(0.4)	(0.4)
Net earnings attributable to Laboratory Corporation of America Holdings	$ 147.2	$ 161.6
Basic earnings per common share (in dollars per share)	$ 1.58	$ 1.66
Diluted earnings per common share (in dollars per share)	$ 1.56	$ 1.63