BUSINESS SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Percentage of net revenues from the DIS business			90.00%	90.00%
Total net revenues	$ 1,787,140	$ 1,821,748	$ 5,389,527	$ 5,608,797
Total operating income	689,477	304,620	1,205,192	935,791
Non-operating expenses, net	(32,142)	(33,645)	(94,880)	(99,015)
Income from continuing operations before taxes	657,335	270,975	1,110,312	836,776
Income tax expense	245,874	103,978	413,702	320,266
Income from continuing operations	411,461	166,997	696,610	516,510
Income from discontinued operations, net of taxes	2,406	4,541	35,497	10,016
Net income	413,867	171,538	732,107	526,526
Less: Net income attributable to noncontrolling interests	8,724	8,456	25,717	26,621
Net income attributable to Quest Diagnostics	405,143	163,082	706,390	499,905
DIS business
Segment Reporting Information [Line Items]
Total net revenues	1,646,809	1,686,908	4,970,366	5,192,451
Total operating income	293,540	349,671	886,685	1,071,188
All other operating segments [Member]
Segment Reporting Information [Line Items]
Total net revenues	140,331	134,840	419,161	416,346
Total operating income	22,461	11,251	53,443	42,055
General corporate expenses [Member]
Segment Reporting Information [Line Items]
Total operating income	$ 373,476	$ (56,302)	$ 265,064	$ (177,452)