CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net revenues	$ 1,891	$ 1,884
Operating costs and expenses and other operating income:
Cost of services	1,244	1,226
Selling, general and administrative	384	363
Amortization of intangible assets	24	22
Other operating (income) expense, net	(9)	1
Total operating costs and expenses, net	1,643	1,612
Operating income	248	272
Other income (expense):
Interest expense, net	(44)	(41)
Other income (expense), net	9	(2)
Total non-operating expenses, net	(35)	(43)
Income before income taxes and equity in earnings of equity method investees	213	229
Income tax expense	(50)	(52)
Equity in earnings of equity method investees, net of taxes	13	12
Net income	176	189
Less: Net income attributable to noncontrolling interests	12	12
Net income attributable to Quest Diagnostics	$ 164	$ 177
Earnings per share attributable to Quest Diagnostics’ common stockholders:
Basic (per share)	$ 1.22	$ 1.30
Diluted (per share)	$ 1.20	$ 1.27
Weighted average common shares outstanding:
Basic (in Shares)	134	136
Diluted (in Shares)	136	139