BUSINESS SEGMENT INFORMATION (Details) (USD $)	3 Months Ended																12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Percentage of net revenues from clinical testing business	90.00%								90.00%								90.00%		90.00%		90.00%
Provision for special charge Medi-Cal matter							$ 236,000,000										$ 236,000,000
Total net revenues	1,879,307,000	[1],[2]	1,906,405,000	[1],[3]	1,903,201,000	[1],[4],[5]	1,821,577,000	[1],[6]	1,824,040,000	[1],[7]	1,864,655,000	[1],[8]	1,874,727,000	[1]	1,805,503,000	[1],[9]	7,510,490,000	[1]	7,368,925,000	[1]	7,455,243,000
Total operating income																	995,048,000		1,295,535,000		1,359,111,000
Income from continuing operations before taxes																	856,232,000		1,184,335,000		1,227,932,000
Non-operating expenses, net																	(138,816,000)		(111,200,000)		(131,179,000)
Income tax expense																	349,000,000		425,531,000		460,474,000
Income (loss) from continuing operations	199,343,000	[1],[2]	182,143,000	[1],[3]	172,034,000	[1],[4],[5]	(46,288,000)	[1],[6]	175,341,000	[1],[7]	208,116,000	[1],[8]	204,142,000	[1]	171,205,000	[1],[9]	507,232,000	[1]	758,804,000	[1]	767,458,000
Loss from discontinued operations, net of taxes																	(1,582,000)		(1,787,000)		(1,236,000)
Net income	198,892,000	[1],[2]	181,893,000	[1],[3]	171,527,000	[1],[4],[5]	(46,662,000)	[1],[6]	174,232,000	[1],[7]	207,756,000	[1],[8]	203,876,000	[1]	171,153,000	[1],[9]	505,650,000	[1]	757,017,000	[1]	766,222,000
Less: Net income attributable to noncontrolling interests	9,455,000	[1],[2]	10,045,000	[1],[3]	8,384,000	[1],[4],[5]	7,199,000	[1],[6]	8,476,000	[1],[7]	9,681,000	[1],[8]	9,261,000	[1]	8,705,000	[1],[9]	35,083,000	[1]	36,123,000	[1]	37,111,000
Net income attributable to Quest Diagnostics	189,437,000	[1],[2]	171,848,000	[1],[3]	163,143,000	[1],[4],[5]	(53,861,000)	[1],[6]	165,756,000	[1],[7]	198,075,000	[1],[8]	194,615,000	[1]	162,448,000	[1],[9]	470,567,000	[1]	720,894,000	[1]	729,111,000
Pre tax losses on extinguishment of debt																					20,000,000
Discrete tax benefits	12,600,000		7,900,000								14,400,000						12,600,000
Depreciation and amortization																	281,102,000		253,964,000		256,687,000
Capital expenditures																	161,556,000		205,400,000		166,928,000
Clinical laboratory testing business [Member]
Total net revenues																	6,814,456,000		6,738,604,000		6,824,149,000
Total operating income																	1,403,797,000		1,424,173,000		1,491,131,000
Depreciation and amortization																	188,820,000		194,655,000		200,905,000
Capital expenditures																	132,024,000		166,445,000		136,248,000
All other operating segments [Member]
Total net revenues																	696,034,000		630,321,000		631,094,000
Total operating income																	73,356,000		44,314,000		59,862,000
Depreciation and amortization																	21,356,000		17,457,000		17,337,000
Capital expenditures																	22,706,000		29,803,000		23,592,000
General corporate expenses [Member]
Total operating income																	(482,105,000)		(172,952,000)		(191,882,000)
Depreciation and amortization																	70,926,000		41,852,000		38,445,000
Capital expenditures																	$ 6,826,000		$ 9,152,000		$ 7,088,000

[1] (a) During the third quarter of 2006, the Company completed its wind down of NID and classified the operations of NID as discontinued operations. Results of operations have been prepared to report the results of NID as discontinued operations for all periods presented (see Note 17).

[2] (f) Includes restructuring and integration charges of $5.7 million of which $8.7 million is principally associated with professional fees incurred in conjunction with further restructuring and integrating the Company. The remainder is primarily associated with the reversal of certain previously established reserves for restructuring activities, principally associated with workforce reductions. Of the total $5.7 million, $8.4 million was included in selling, general and administrative expenses, with the remaining $2.7 million representing a reduction in cost of services. Also includes pre-tax charges of $5.6 million, principally representing severance and other separation benefits as well as accelerated vesting of certain equity awards in connection with the succession of the Company's CEO. In addition, results for the fourth quarter also include discrete income tax benefits of $12.6 million.

[3] (e) Includes pre-tax charges of $27.3 million, principally associated with workforce reductions. Of these costs, $15.9 million and $11.4 million were included in cost of services and selling, general and administrative expenses, respectively. Also includes discrete income tax benefits of $7.9 million.

[4] (c) On April 4, 2011, we completed the acquisition of Athena. On May 17, 2011, we completed the acquisition of Celera (see Note 4).

[5] (d) Includes pre-tax transaction costs of $15.1 million associated with the acquisitions of Athena and Celera (see Note 4). Of these costs, $14.3 million, primarily related to professional fees, were recorded in selling, general and administrative expenses and $0.8 million of financing related costs were included in interest expense, net. In addition, results for the second quarter include $6.0 million of pre-tax integration charges, primarily associated with workforce reductions, related to the acqusitions of Athena and Celera.

[6] (b) Includes a pre-tax charge in "other operating expense (income), net" in the first quarter of 2011 of $236 million, associated with the settlement of the California Lawsuit (see Note 16). Also includes $13.3 million of pre-tax charges, principally associated with workforce reductions. Of these costs, $9.0 million and $4.3 million were included in cost of services and selling, general and administrative expenses, respectively. Results for the first quarter also includes $4.7 million of pre-tax transaction costs, associated with the acquisitions of Athena and Celera (see Note 4). Of these costs, $2.3 million, primarily related to professional and filing fees, was recorded in selling, general and administrative expenses and $2.4 million of financing related costs were recorded in interest expense, net. In addition, management estimates that the impact of severe weather during the first quarter adversely affected operating income by $18.5 million.

[7] (i) Includes $9.6 million of pre-tax charges, primarily related to workforce reductions. Of these costs, $1.9 million and $7.7 million were included in cost of services and selling, general and administrative expenses, respectively. In addition, the Company recorded pre-tax charges of $9.6 million associated with the settlement of employment litigation. Results for the fourth quarter of 2010 also include discrete income tax benefits of $9.1 million.

[8] (h) Includes discrete income tax benefits of $14.4 million.

[9] (g) Includes pre-tax charges of $17.3 million, principally associated with workforce reductions. Of these costs, $4.5 million and $12.8 million were included in cost of services and selling, general and administrative expenses, respectively. In addition, management estimates that the impact of severe weather during the first quarter of 2010 adversely affected operating income by $14.1 million.