EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share, Basic and Diluted [Abstract]
Income from continuing operations	$ 152,665	$ 175,225	$ 268,156	$ 331,348
Income from discontinued operations, net of taxes	12,803	2,480	33,091	5,475
Net income attributable to Quest Diagnostics’ common stockholders	165,468	177,705	301,247	336,823
Less: Earnings allocated to participating securities	562	712	927	1,306
Earnings available to Quest Diagnostics' common stockholders - basic and diluted	$ 152,103	$ 174,513	$ 267,229	$ 330,042
Weighted average common shares outstanding - basic	152,708	158,477	155,403	158,385
Stock options and performance share units	1,351	1,307	1,330	1,360
Weighted average common shares outstanding - diluted	154,059	159,784	156,733	159,745
Income from continuing operations, per basic share	$ 0.99	$ 1.10	$ 1.72	$ 2.08
Income from discontinued operations, per basic share	$ 0.08	$ 0.02	$ 0.21	$ 0.04
Net income, per basic share	$ 1.07	$ 1.12	$ 1.93	$ 2.12
Income from continuing operations, per diluted share	$ 0.99	$ 1.09	$ 1.71	$ 2.06
Income from discontinued operations, per diluted share	$ 0.08	$ 0.02	$ 0.21	$ 0.04
Net income, per diluted share	$ 1.07	$ 1.11	$ 1.92	$ 2.10
Stock options and performance share units	1,457	2,463	1,771	2,229