CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Net revenues	$ 2,295	$ 2,486	$ 6,964	$ 7,550
Operating costs and expenses and other operating income:
Cost of services	1,541	1,618	4,647	4,875
Selling, general and administrative	380	464	1,235	1,311
Amortization of intangible assets	27	27	81	81
Other operating expense (income), net	5	(15)	6	(10)
Total operating costs and expenses, net	1,953	2,094	5,969	6,257
Operating income	342	392	995	1,293
Other income (expense):
Interest expense, net	(40)	(33)	(112)	(106)
Other (expense) income, net	(3)	(8)	10	(61)
Total non-operating expense, net	(43)	(41)	(102)	(167)
Income before income taxes and equity in earnings of equity method investees	299	351	893	1,126
Income tax expense	(68)	(81)	(208)	(268)
Equity in earnings of equity method investees, net of taxes	6	6	18	41
Net income	237	276	703	899
Less: Net income attributable to noncontrolling interests	12	20	41	54
Net income attributable to Quest Diagnostics	$ 225	$ 256	$ 662	$ 845
Earnings per share attributable to Quest Diagnostics’ common stockholders:
Basic (in dollars per share)	$ 1.99	$ 2.20	$ 5.87	$ 7.17
Diluted (in dollars per share)	$ 1.96	$ 2.17	$ 5.79	$ 7.05
Weighted average common shares outstanding:
Basic (in Shares)	112	116	112	117
Diluted (in Shares)	114	118	114	119