SUMMARIZED FINANCIAL INFORMATION (Condensed Consolidating Statement of Operations and Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net revenues	$ 1,936,456	$ 1,821,577
Cost of services	1,116,538	1,096,998
Selling, general and administrative	500,641	447,858
Amortization of intangible assets	20,231	9,849
Royalty (income) expense
Other operating (income) expense, net	(539)	235,912
Total operating costs and expenses	1,636,871	1,790,617
Operating income (loss)	299,585	30,960
Non-operating (expense) income, net	(29,967)	(28,022)
Income (loss) from continuing operations before taxes	269,618	2,938
Income tax (benefit) expense	101,377	49,226
Income (loss) from continuing operations	168,241	(46,288)
Income (loss) from discontinued operations, net of taxes	274	(374)
Equity earnings from subsidiaries
Net income (loss)	168,515	(46,662)
Less: Net income attributable to noncontrolling interests	9,397	7,199
Net income (loss) attributable to Quest Diagnostics	159,118	(53,861)
Net income (loss)	168,515	(46,662)
Other comprehensive income (loss), net of tax	18,627	21,583
Comprehensive income (loss)	187,142	(25,079)
Less: Comprehensive income attributable to noncontrolling interests	9,397	7,199
Comprehensive income (loss) attributable to Quest Diagnostics	177,745	(32,278)
Parent [Member]
Net revenues	202,165	198,489
Cost of services	120,828	123,591
Selling, general and administrative	63,878	38,436
Amortization of intangible assets	287	163
Royalty (income) expense	(108,061)	(102,356)
Other operating (income) expense, net	(146)	236,278
Total operating costs and expenses	76,786	296,112
Operating income (loss)	125,379	(97,623)
Non-operating (expense) income, net	(42,396)	(38,420)
Income (loss) from continuing operations before taxes	82,983	(136,043)
Income tax (benefit) expense	31,562	(3,614)
Income (loss) from continuing operations	51,421	(132,429)
Income (loss) from discontinued operations, net of taxes
Equity earnings from subsidiaries	107,697	78,568
Net income (loss)	159,118	(53,861)
Less: Net income attributable to noncontrolling interests
Net income (loss) attributable to Quest Diagnostics	159,118	(53,861)
Net income (loss)	159,118	(53,861)
Other comprehensive income (loss), net of tax	411	(2,921)
Comprehensive income (loss)	159,529	(56,782)
Less: Comprehensive income attributable to noncontrolling interests
Comprehensive income (loss) attributable to Quest Diagnostics	159,529	(56,782)
Subsidiary Guarantors [Member]
Net revenues	1,615,622	1,503,344
Cost of services	930,385	907,390
Selling, general and administrative	335,493	311,729
Amortization of intangible assets	17,093	8,149
Royalty (income) expense	108,061	102,356
Other operating (income) expense, net	(266)	(214)
Total operating costs and expenses	1,390,766	1,329,410
Operating income (loss)	224,856	173,934
Non-operating (expense) income, net	(60,296)	(57,154)
Income (loss) from continuing operations before taxes	164,560	116,780
Income tax (benefit) expense	64,388	46,165
Income (loss) from continuing operations	100,172	70,615
Income (loss) from discontinued operations, net of taxes	274	(374)
Equity earnings from subsidiaries
Net income (loss)	100,446	70,241
Less: Net income attributable to noncontrolling interests
Net income (loss) attributable to Quest Diagnostics	100,446	70,241
Net income (loss)	100,446	70,241
Other comprehensive income (loss), net of tax
Comprehensive income (loss)	100,446	70,241
Less: Comprehensive income attributable to noncontrolling interests
Comprehensive income (loss) attributable to Quest Diagnostics	100,446	70,241
Non-Guarantor Subsidiaries [Member]
Net revenues	196,203	191,287
Cost of services	65,325	66,017
Selling, general and administrative	108,969	105,053
Amortization of intangible assets	2,851	1,537
Royalty (income) expense
Other operating (income) expense, net	(127)	(152)
Total operating costs and expenses	177,018	172,455
Operating income (loss)	19,185	18,832
Non-operating (expense) income, net	2,890	3,369
Income (loss) from continuing operations before taxes	22,075	22,201
Income tax (benefit) expense	5,427	6,675
Income (loss) from continuing operations	16,648	15,526
Income (loss) from discontinued operations, net of taxes
Equity earnings from subsidiaries
Net income (loss)	16,648	15,526
Less: Net income attributable to noncontrolling interests	9,397	7,199
Net income (loss) attributable to Quest Diagnostics	7,251	8,327
Net income (loss)	16,648	15,526
Other comprehensive income (loss), net of tax	18,216	24,504
Comprehensive income (loss)	34,864	40,030
Less: Comprehensive income attributable to noncontrolling interests	9,397	7,199
Comprehensive income (loss) attributable to Quest Diagnostics	25,467	32,831
Eliminations [Member]
Net revenues	(77,534)	(71,543)
Cost of services
Selling, general and administrative	(7,699)	(7,360)
Amortization of intangible assets
Royalty (income) expense
Other operating (income) expense, net
Total operating costs and expenses	(7,699)	(7,360)
Operating income (loss)	(69,835)	(64,183)
Non-operating (expense) income, net	69,835	64,183
Income (loss) from continuing operations before taxes
Income tax (benefit) expense
Income (loss) from continuing operations
Income (loss) from discontinued operations, net of taxes
Equity earnings from subsidiaries	(107,697)	(78,568)
Net income (loss)	(107,697)	(78,568)
Less: Net income attributable to noncontrolling interests
Net income (loss) attributable to Quest Diagnostics	(107,697)	(78,568)
Net income (loss)	(107,697)	(78,568)
Other comprehensive income (loss), net of tax
Comprehensive income (loss)	(107,697)	(78,568)
Less: Comprehensive income attributable to noncontrolling interests
Comprehensive income (loss) attributable to Quest Diagnostics	$ (107,697)	$ (78,568)