EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Amounts attributable to Quest Diagnostics’ common stockholders:
Net income attributable to Quest Diagnostics	$ 202	$ 355
Less: Earnings allocated to participating securities	1	1
Earnings available to Quest Diagnostics’ common stockholders – basic and diluted	$ 201	$ 354
Weighted average common shares outstanding - basic	112	119
Stock options and performance share units	1	2
Weighted average common shares outstanding - diluted	113	121
Basic (in dollars per share)	$ 1.80	$ 2.97
Diluted (in dollars per share)	$ 1.78	$ 2.92
Antidilutive securities excluded from computation of earnings per share (less than)	1	1