CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Statement [Abstract]
Net sales	$ 5,542.3	$ 5,003.9	$ 4,694.7
Cost of sales	3,267.6	2,906.1	2,723.8
Gross profit	2,274.7	2,097.8	1,970.9
Selling, general and administrative expenses	1,159.6	1,034.3	958.9
Amortization of intangibles and other assets	85.8	72.7	62.6
Restructuring and other special charges	80.9	12.0	13.5
Operating income	948.4	978.8	935.9
Other income (expenses):
Interest expense	(87.5)	(70.0)	(62.9)
Equity method income, net	9.5	10.6	13.8
Investment income	1.3	1.1	1.6
Other, net	(5.6)	(4.9)	(3.8)
Earnings before income taxes	866.1	915.6	884.6
Provision for income taxes	333.0	344.0	329.0
Net earnings	533.1	571.6	555.6
Less: Net earnings attributable to the noncontrolling interest	(13.4)	(13.4)	(12.3)
Net earnings attributable to Laboratory Corporation of America Holdings	$ 519.7	$ 558.2	$ 543.3
Basic earnings per common share (in dollars per share)	$ 5.20	$ 5.42	$ 5.06
Diluted earnings per common share (in dollars per share)	$ 5.11	$ 5.29	$ 4.98