CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 129	$ 142	$ 199	$ 253
Other comprehensive income (loss):
Currency translation	4	3	(2)	2
Market valuation, net of tax	0	3	2	3
Net deferred loss on cash flow hedges, net of tax	1	(3)	2	(5)
Other comprehensive income	5	3	2	0
Comprehensive income	134	145	201	253
Less: Comprehensive income attributable to noncontrolling interests	11	9	20	16
Comprehensive income attributable to Quest Diagnostics	$ 123	$ 136	$ 181	$ 237