CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net revenues	$ 1,889	$ 1,856	$ 5,692	$ 5,537
Operating costs and expenses and other operating income:
Cost of services	1,222	1,190	3,691	3,525
Selling, general and administrative	354	348	1,068	1,061
Amortization of intangible assets	22	19	66	54
Other operating (income) expense, net	(13)	1	(14)	1
Total operating costs and expenses, net	1,585	1,558	4,811	4,641
Operating income	304	298	881	896
Other income (expense):
Interest expense, net	(41)	(38)	(124)	(112)
Other income (expense), net	3	(2)	2	12
Total non-operating expenses, net	(38)	(40)	(122)	(100)
Income before income taxes and equity in earnings of equity method investees	266	258	759	796
Income tax expense	(48)	(92)	(142)	(264)
Equity in earnings of equity method investees, net of taxes	9	9	32	25
Net income	227	175	649	557
Less: Net income attributable to noncontrolling interests	14	14	40	39
Net income attributable to Quest Diagnostics	$ 213	$ 161	$ 609	$ 518
Earnings per share attributable to Quest Diagnostics’ common stockholders:
Basic (per share)	$ 1.56	$ 1.18	$ 4.46	$ 3.77
Diluted (per share)	$ 1.53	$ 1.15	$ 4.37	$ 3.68
Weighted average common shares outstanding:
Basic (in Shares)	136	137	136	137
Diluted (in Shares)	139	140	139	140
Dividends per common share	$ 0.5	$ 0.45	$ 1.5	$ 1.35