SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues	$ 1,931	$ 1,885	$ 5,773	$ 5,654
Selling, general and administrative expenses	423	409	1,297	1,281
Net income attributable to Quest Diagnostics	$ 161	$ 192	$ 518	$ 490
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues					$ 7,214
Selling, general and administrative expenses					1,380
Net income attributable to Quest Diagnostics					645
Adjustments for New Accounting Pronouncement [Member] | As Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues					7,515
Selling, general and administrative expenses					1,681
Net income attributable to Quest Diagnostics					645
Adjustments for New Accounting Pronouncement [Member] | Adjustment for ASU on Revenue Recognition [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues					(301)
Selling, general and administrative expenses					(301)
Net income attributable to Quest Diagnostics					$ 0