SUMMARIZED FINANCIAL INFORMATION (Condensed Consolidating Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Cash and cash equivalents	$ 145,439	$ 164,886	$ 994,242	$ 449,301
Accounts receivable, net	973,888	906,455
Other current assets	399,277	329,919
Total current assets	1,518,604	1,401,260
Property, plant and equipment, net	781,427	799,771
Goodwill and intangible assets, net	6,876,588	6,831,377
Intercompany (payable) receivable
Investment in subsidiaries
Other assets	274,825	280,971
Total assets	9,451,444	9,313,379
Accounts payable and accrued expenses	971,092	906,764
Short-term borrowings and current portion of long-term debt	554,356	654,395
Total current liabilities	1,525,448	1,561,159
Long-term debt	3,365,257	3,370,522
Other liabilities	664,682	666,699
Quest Diagnostics stockholders' equity	3,869,293	3,692,872
Noncontrolling interests	26,764	22,127
Total stockholders' equity	3,896,057	3,714,999	3,238,004	4,054,125
Total liabilities and stockholders' equity	9,451,444	9,313,379
Parent [Member]
Cash and cash equivalents	69,585	71,762	937,004	392,525
Accounts receivable, net	13,135	10,846
Other current assets	99,391	51,292
Total current assets	182,111	133,900
Property, plant and equipment, net	159,936	164,785
Goodwill and intangible assets, net	154,913	155,596
Intercompany (payable) receivable	(749,903)	(566,071)
Investment in subsidiaries	8,082,783	7,963,131
Other assets	297,581	318,944
Total assets	8,127,421	8,170,285
Accounts payable and accrued expenses	761,802	694,846
Short-term borrowings and current portion of long-term debt	281,451	561,438
Total current liabilities	1,043,253	1,256,284
Long-term debt	3,020,304	3,026,235
Other liabilities	194,571	194,894
Quest Diagnostics stockholders' equity	3,869,293	3,692,872
Noncontrolling interests
Total stockholders' equity	3,869,293	3,692,872
Total liabilities and stockholders' equity	8,127,421	8,170,285
Subsidiary Guarantors [Member]
Cash and cash equivalents	10,885	44,053	5,605	928
Accounts receivable, net	154,586	178,813
Other current assets	215,049	188,978
Total current assets	380,520	411,844
Property, plant and equipment, net	577,264	591,962
Goodwill and intangible assets, net	6,261,035	6,228,611
Intercompany (payable) receivable	919,256	819,486
Investment in subsidiaries
Other assets	40,275	39,965
Total assets	8,178,350	8,091,868
Accounts payable and accrued expenses	173,515	172,207
Short-term borrowings and current portion of long-term debt	7,263	7,327
Total current liabilities	180,778	179,534
Long-term debt	17,243	18,606
Other liabilities	530,659	544,504
Quest Diagnostics stockholders' equity	7,449,670	7,349,224
Noncontrolling interests
Total stockholders' equity	7,449,670	7,349,224
Total liabilities and stockholders' equity	8,178,350	8,091,868
Non-Guarantor Subsidiaries [Member]
Cash and cash equivalents	64,969	49,071	51,633	55,848
Accounts receivable, net	806,167	716,796
Other current assets	86,006	91,686
Total current assets	957,142	857,553
Property, plant and equipment, net	44,227	43,024
Goodwill and intangible assets, net	460,640	447,170
Intercompany (payable) receivable	(169,353)	(253,415)
Investment in subsidiaries
Other assets	50,368	48,580
Total assets	1,343,024	1,142,912
Accounts payable and accrued expenses	36,944	41,748
Short-term borrowings and current portion of long-term debt	265,642	85,630
Total current liabilities	302,586	127,378
Long-term debt	327,710	325,681
Other liabilities	52,851	53,819
Quest Diagnostics stockholders' equity	633,113	613,907
Noncontrolling interests	26,764	22,127
Total stockholders' equity	659,877	636,034
Total liabilities and stockholders' equity	1,343,024	1,142,912
Eliminations [Member]
Cash and cash equivalents
Accounts receivable, net
Other current assets	(1,169)	(2,037)
Total current assets	(1,169)	(2,037)
Property, plant and equipment, net
Goodwill and intangible assets, net
Intercompany (payable) receivable
Investment in subsidiaries	(8,082,783)	(7,963,131)
Other assets	(113,399)	(126,518)
Total assets	(8,197,351)	(8,091,686)
Accounts payable and accrued expenses	(1,169)	(2,037)
Short-term borrowings and current portion of long-term debt
Total current liabilities	(1,169)	(2,037)
Long-term debt
Other liabilities	(113,399)	(126,518)
Quest Diagnostics stockholders' equity	(8,082,783)	(7,963,131)
Noncontrolling interests
Total stockholders' equity	(8,082,783)	(7,963,131)
Total liabilities and stockholders' equity	$ (8,197,351)	$ (8,091,686)