CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 354	$ 139	$ 553	$ 392
Other comprehensive (loss) income:
Currency translation	(5)	(5)	(7)	(3)
Market valuation, net of taxes	(2)	(2)	0	1
Net deferred loss on cash flow hedges, net of taxes	1	0	3	(5)
Other comprehensive loss	(6)	(7)	(4)	(7)
Comprehensive income	348	132	549	385
Less: Comprehensive income attributable to noncontrolling interests	12	10	32	26
Comprehensive income attributable to Quest Diagnostics	$ 336	$ 122	$ 517	$ 359