BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Percentage of net revenues	100.00%	100.00%
Total net revenues	$ 2,331	$ 2,611
Total operating income	305	513
Non-operating expense, net	(28)	(61)
Income before income taxes and equity in earnings of equity method investees	277	452
Income tax expense	(65)	(110)
Equity in earnings of equity method investees, net of taxes	5	31
Net income	217	373
Less: Net income attributable to noncontrolling interests	15	18
Net income attributable to Quest Diagnostics	$ 202	$ 355
Total net revenues, percent	100.00%	100.00%
Routine clinical testing services
Segment Reporting Information [Line Items]
Total net revenues, percent	49.00%	41.00%
COVID-19 Testing Services
Segment Reporting Information [Line Items]
Total net revenues, percent	5.00%	23.00%
Gene-based and esoteric testing services
Segment Reporting Information [Line Items]
Total net revenues, percent	37.00%	28.00%
Anatomic pathology testing services
Segment Reporting Information [Line Items]
Total net revenues, percent	6.00%	5.00%
All other services
Segment Reporting Information [Line Items]
Total net revenues, percent	3.00%	3.00%
DIS business
Segment Reporting Information [Line Items]
Percentage of net revenues	97.00%	97.00%
Total net revenues	$ 2,259	$ 2,541
Total operating income	$ 374	$ 562
DIS business | Minimum
Segment Reporting Information [Line Items]
Percentage of net revenues	95.00%	95.00%
All other operating segments
Segment Reporting Information [Line Items]
Total net revenues	$ 72	$ 70
Total operating income	8	7
General corporate activities
Segment Reporting Information [Line Items]
Total operating income	$ (77)	$ (56)