EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Amounts attributable to Quest Diagnostics’ common stockholders:
Net income attributable to Quest Diagnostics	$ 256	$ 505	$ 845	$ 1,605
Less: Earnings allocated to participating securities	2	2	4	6
Earnings available to Quest Diagnostics’ common stockholders – basic and diluted	$ 254	$ 503	$ 841	$ 1,599
Weighted average common shares outstanding - basic	116	123	117	127
Stock options and performance share units	2	2	2	2
Weighted average common shares outstanding - diluted	118	125	119	129
Basic (in dollars per share)	$ 2.20	$ 4.11	$ 7.17	$ 12.63
Diluted (in dollars per share)	$ 2.17	$ 4.02	$ 7.05	$ 12.41
Stock options and performance share units	1	0	0	0