BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Percentage of net revenues from Diagnostic Information Services business	90.00%	90.00%
Total net revenues	$ 1,899	$ 1,863
Total operating income	279	257
Non-operating expenses, net	(33)	(85)
Income before income taxes and equity in earnings of equity method investees	246	172
Income tax expense	(78)	(67)
Equity in earnings of equity method investees, net of taxes	7	10
Net income	175	115
Less: Net income attributable to noncontrolling interests	11	12
Net income attributable to Quest Diagnostics	164	103
DIS business [Member]
Segment Reporting Information [Line Items]
Total net revenues	1,812	1,756
Total operating income	306	278
All other operating segments [Member]
Segment Reporting Information [Line Items]
Total net revenues	87	107
Total operating income	13	21
General corporate activities [Member]
Segment Reporting Information [Line Items]
Total operating income	$ (40)	$ (42)