EARNINGS PER SHARE (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share, Basic and Diluted [Abstract]
Income from continuing operations	$ 129	$ 403	$ 366	$ 671
Income from discontinued operations, net of taxes	0	2	0	35
Net income attributable to Quest Diagnostics	129	405	366	706
Less: Earnings allocated to participating securities	1	1	2	2
Earnings available to Quest Diagnostics' common stockholders - basic and diluted	$ 128	$ 402	$ 364	$ 669
Weighted average common shares outstanding - basic	145	150	144	153
Stock options and performance share units	0	1	1	2
Weighted average common shares outstanding - diluted	145	151	145	155
Income from continuing operations, per basic share	$ 0.89	$ 2.68	$ 2.52	$ 4.36
Income from discontinued operations, per basic share	$ 0.00	$ 0.02	$ 0.00	$ 0.23
Net income	$ 0.89	$ 2.70	$ 2.52	$ 4.59
Income from continuing operations, per diluted share	$ 0.88	$ 2.66	$ 2.51	$ 4.32
Income from discontinued operations, per diluted share	$ 0.00	$ 0.02	$ 0.00	$ 0.23
Net income	$ 0.88	$ 2.68	$ 2.51	$ 4.55
Stock options and performance share units not included due to their antidilutive effect	0	2	3	2