CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net revenues	$ 1,919	$ 1,864	$ 3,803	$ 3,681
Operating costs and expenses and other operating income:
Cost of services	1,243	1,170	2,469	2,335
Selling, general and administrative	351	358	714	713
Amortization of intangible assets	22	18	44	35
Other operating income, net	(2)	(1)	(1)	0
Total operating costs and expenses, net	1,614	1,545	3,226	3,083
Operating income	305	319	577	598
Other income (expense):
Interest expense, net	(42)	(38)	(83)	(74)
Other income (expense), net	1	11	(1)	14
Total non-operating expenses, net	(41)	(27)	(84)	(60)
Income before income taxes and equity in earnings of equity method investees	264	292	493	538
Income tax expense	(42)	(94)	(94)	(172)
Equity in earnings of equity method investees, net of taxes	11	9	23	16
Net income	233	207	422	382
Less: Net income attributable to noncontrolling interests	14	14	26	25
Net income attributable to Quest Diagnostics	$ 219	$ 193	$ 396	$ 357
Earnings per share attributable to Quest Diagnostics’ common stockholders:
Basic (per share)	$ 1.60	$ 1.40	$ 2.90	$ 2.59
Diluted (per share)	$ 1.57	$ 1.37	$ 2.84	$ 2.53
Weighted average common shares outstanding:
Basic (in Shares)	136	137	136	137
Diluted (in Shares)	139	140	139	140
Dividends per common share	$ 0.50	$ 0.45	$ 1.00	$ 0.90