CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net revenues	$ 2,720	$ 1,822
Operating costs and expenses and other operating income:
Cost of services	1,626	1,270
Selling, general and administrative	407	347
Amortization of intangible assets	27	25
Other operating expense, net	0	5
Total operating costs and expenses, net	2,060	1,647
Operating income	660	175
Other income (expense):
Interest expense, net	(38)	(41)
Other income (expense), net	4	(16)
Total non-operating expense, net	(34)	(57)
Income before income taxes and equity in earnings of equity method investees	626	118
Income tax expense	(153)	(26)
Equity in earnings of equity method investees, net of taxes	17	14
Net income	490	106
Less: Net income attributable to noncontrolling interests	21	7
Net income attributable to Quest Diagnostics	$ 469	$ 99
Earnings per share attributable to Quest Diagnostics’ common stockholders:
Basic(in dollars per share)	$ 3.52	$ 0.74
Diluted (in dollars per share)	$ 3.46	$ 0.73
Weighted average common shares outstanding:
Basic (in Shares)	133	134
Diluted (in Shares)	135	135