SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 1) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues	$ 1,936	$ 1,931	$ 1,943	$ 1,899	$ 1,861	$ 1,885	$ 1,906	$ 1,863	$ 7,709	$ 7,515	$ 7,493
Selling, general and administrative expenses									1,750	1,681	1,679
Net income attributable to Quest Diagnostics	$ 254	$ 161	$ 193	$ 164	$ 155	$ 192	$ 195	$ 103	772	645	$ 709
Payments of debt retirement costs										47
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues									7,402	7,214
Selling, general and administrative expenses									1,443	1,380
Net income attributable to Quest Diagnostics									772	645
Adjustments for New Accounting Pronouncement [Member] | As Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues									7,709	7,515
Selling, general and administrative expenses									1,750	1,681
Net income attributable to Quest Diagnostics									772	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									(307)	(301)
Selling, general and administrative expenses									(307)	(301)
Net income attributable to Quest Diagnostics									$ 0	$ 0