EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Earnings Per Share [Abstract]
Income from continuing operations	$ 172,098	$ 198,435	$ 282,261	$ 555,816
Loss from discontinued operations, net of taxes	(250)	(360)	(1,131)	(678)
Net income attributable to Quest Diagnostics	171,848	198,075	281,130	555,138
Less: Earnings allocated to participating securities	967	957	1,934	2,545
Earnings available to Quest Diagnostics' common stockholders - basic and diluted	$ 171,131	$ 197,478	$ 280,327	$ 553,271
Weighted average common shares outstanding - basic	157,816,000	173,229,000	158,971,000	177,456,000
Stock options and performance share units	1,186,000	1,086,000	1,548,000	1,697,000
Weighted average common shares outstanding - diluted	159,002,000	174,315,000	160,519,000	179,153,000
Income from continuing operations	$ 1.08	$ 1.14	$ 1.76	$ 3.12
Loss from discontinued operations, per basic share			$ (0.01)
Net income - per basic share	$ 1.08	$ 1.14	$ 1.75	$ 3.12
Income from continuing operations	$ 1.08	$ 1.13	$ 1.75	$ 3.09
Net income - per diluted share	$ 1.07	$ 1.13	$ 1.74	$ 3.09
Loss from discontinued operations, per diluted share	$ (0.01)		$ (0.01)
Stock options and performance share units not included due to their antidilutive effect	2,300,000	3,300,000	2,200,000	3,000,000