CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues	$ 2,866.3	$ 2,528.2	$ 5,714.6	$ 4,941.9
Cost of Revenue	2,031.2	1,750.2	4,100.5	3,451.4
Gross Profit	835.1	778.0	1,614.1	1,490.5
Selling, general and administrative expenses	395.2	357.7	792.2	700.6
Amortization of intangibles and other assets	58.5	51.4	120.8	99.0
Net restructuring and other special charges	12.2	39.1	26.5	43.0
Operating Income (Loss)	369.2	329.8	674.6	647.9
Other income (expenses):
Interest expense	(63.1)	(55.0)	(126.6)	(107.4)
Equity method income, net	3.0	4.5	5.5	6.8
Investment income	0.8	0.4	1.4	0.7
Other, net	2.8	(0.5)	(0.7)	(3.6)
Earnings before income taxes	312.7	279.2	554.2	544.4
Provision for income taxes	78.6	94.1	147.6	176.0
Net earnings	234.1	185.1	406.6	368.4
Less: Net earnings attributable to the noncontrolling interest	(0.3)	(0.3)	0.4	(0.6)
Net earnings attributable to Laboratory Corporation of America Holdings	$ 233.8	$ 184.8	$ 407.0	$ 367.8
Basic earnings per common share (in dollars per share)	$ 2.29	$ 1.80	$ 3.99	$ 3.59
Diluted earnings per common share (in dollars per share)	$ 2.27	$ 1.78	$ 3.94	$ 3.54
Previous Accounting Guidance [Member]
Gross profit, as reported		$ 861.8		$ 1,665.4
Net income (loss), including portion attributable to NCI, as reported		188.9		381.4
Net income (loss) attributable to Parent, as reported		188.6		380.8
Revenues		2,542.9		4,989.9
Cost of Revenue		1,681.1		3,324.5
Selling, general and administrative expenses		435.3		854.7
Other income (expenses):
Provision for income taxes		96.2		183.4
Less: Net earnings attributable to the noncontrolling interest		$ (0.3)		$ (0.6)
Basic earnings per common share (in dollars per share)		$ 1.84		$ 3.71
Diluted earnings per common share (in dollars per share)		$ 1.82		$ 3.66