Laboratory Corporation of America (LH) 10-Q 4 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Apr. 30, 2015
Document Information [Line Items]
Entity Registrant Name	LABORATORY CORP OF AMERICA HOLDINGS
Entity Central Index Key	920148
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		100.4

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Current assets:
Cash and cash equivalents	$446.40	$580
Accounts receivable, net of allowance for doubtful accounts of $198.4 and $191.5 at March 31, 2013 and December 31, 2012, respectively	1,187	815.7
Unbilled Contracts Receivable	164.3	0
Supplies inventories	186.5	139.5
Prepaid expenses and other	319.8	157.5
Deferred Tax Assets, Net of Valuation Allowance, Current	24.5	0
Total current assets	2,328.50	1,692.70
Property, plant and equipment, net	1,597.20	786.5
Goodwill, net	6,282.20	3,099.40
Intangible assets, net	3,603.30	1,475.80
Joint venture partnerships and equity method investments	88.9	92.6
Other assets, net	250.5	154.8
Total assets	14,150.60	7,301.80
Current liabilities:
Accounts payable	420.8	282.3
Accrued expenses and other	488.9	341.4
Deferred Revenue, Current	153.9	0
Deferred Tax Liabilities, Net, Current	0	5.5
Short-term borrowings and current portion of long-term debt	348.6	347.1
Liabilities, Current	1,412.20	976.3
Long-term debt, less current portion	6,597.70	2,682.70
Deferred income taxes and other tax liabilities	1,268.50	530.4
Other liabilities	338.4	274.2
Total liabilities	9,616.80	4,463.60
Commitments and contingent liabilities
Noncontrolling interest	16.2	17.7
Shareholders' equity:
Common stock, 92.8 and 93.5 shares outstanding at March 31, 2013 and December 31, 2012, respectively	12	10.4
Additional paid-in capital	1,823.20	0
Retained earnings	3,786.80	3,786.10
Less common stock held in treasury	-973.3	-965.5
Accumulated other comprehensive income	131.1	10.5
Total shareholders' equity	4,517.60	2,820.50
Total liabilities and shareholders' equity	$14,150.60	$7,301.80

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parentheticals) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Current Assets:
Allowance for doubtful accounts	$224.80	$211.60
Shareholders' Equity:
Common stock, shares outstanding (in shares)	100.5	84.6

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Net sales	$1,772.30	$1,430.70
Reimbursement Revenue	20.9	0
Revenues	1,793.20	1,430.70
Cost of sales	1,176.30	913.9
Cost of Reimbursable Expense	20.9	0
Cost of Revenue	1,197.20	913.9
Gross profit	596	516.8
Selling, general and administrative expenses	415.1	284.9
Amortization of intangibles and other assets	31.4	21
Restructuring and other special charges	19.3	7.6
Operating income	130.2	203.3
Other income (expenses):
Interest expense	-104.3	-25.7
Equity method income, net	2.7	3
Investment income	0.6	0.2
Other, net	1.1	6.9
Earnings before income taxes	30.3	187.7
Provision for income taxes	29.3	74.2
Net earnings	1	113.5
Less: Net earnings attributable to the noncontrolling interest	-0.3	-0.4
Net earnings attributable to Laboratory Corporation of America Holdings	$0.70	$113.10
Basic earnings per common share (in dollars per share)	$0.01	$1.33
Diluted earnings per common share (in dollars per share)	$0.01	$1.31

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net earnings	$1		$113.50
Other Comprehensive Earnings, Net of Tax
Foreign currency translation adjustments	-168.5		-36
Net benefit plan adjustments	-0.3	[1]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	0.9		2.3
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	-0.1		-0.6
Other comprehensive earnings (loss) before tax	-167.7		-34.3
Provision for income tax related to items of comprehensive earnings	-47.1		-13.6
Other comprehensive earnings (loss), net of tax	-120.6		-20.7
Comprehensive earnings	-119.6		92.8
Less: Net earnings attributable to the noncontrolling interest	-0.3		-0.4
Comprehensive earnings attributable to Laboratory Corporation of America Holdings	($119.90)		$92.40
[1]	The amortization of prior service cost is included in the computation of net periodic benefit cost. See NoteB 10 (Pension and Post-retirement Plans) below for additional information regarding the Company's net periodic benefit cost.

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]
In Millions
BALANCE at Dec. 31, 2013	$2,491.30	$10.50	$0	$3,373.50	($958.90)	$66.20
Net earnings attributable to Laboratory Corporation of America Holdings	113.1			113.1
Other comprehensive earnings, net of tax	-20.7					-20.7
Other Significant Noncash Transaction, Value of Consideration Given	0
Issuance of common stock under employee stock plans	16.4	0	16.4
Surrender of restricted stock and performance share awards	-4.6				-4.6
Conversion of zero-coupon convertible debt	1.2	0	1.2
Stock compensation	11.7		11.7
Income tax benefit from stock options exercised	0.6		0.6
Purchase of common stock	-107.7	-0.1	-29.9	-77.7
BALANCE at Mar. 31, 2014
BALANCE at Dec. 31, 2014	2,820.50	10.4	0	3,786.10	-965.5	-10.5
Net earnings attributable to Laboratory Corporation of America Holdings	0.7			0.7
Other comprehensive earnings, net of tax	-120.6					-120.6
Stock Issued During Period, Shares, Acquisitions	1.5
Adjustments to Additional Paid in Capital, Other	1,761
Other Significant Noncash Transaction, Value of Consideration Given	1,762.50
Issuance of common stock under employee stock plans	33.2	0.1	33.1
Surrender of restricted stock and performance share awards	-7.8				-7.8
Conversion of zero-coupon convertible debt	0
Stock compensation	26.3		26.3
Income tax benefit from stock options exercised	2.8		2.8
Purchase of common stock	0	0	0	0
BALANCE at Mar. 31, 2015	$4,517.60	$12	$1,823.20	$3,786.80	($973.30)	($131.10)

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit facilities	$60	$0
Payments on zero-coupon subordinated notes	0	-6.9
Payments on long-term debt	-75	0
Proceeds from senior note offerings	2,900	0
Noncontrolling interest distributions	0	-0.3
Deferred payments on acquisitions	0	-0.1
Repayments of Long-term Capital Lease Obligations	-1.2	0
Excess tax benefits from stock based compensation	2.5	0.6
Net proceeds from issuance of stock to employees	30.5	16.4
Purchase of common stock	0	-107.7
Net cash provided by (used for) financing activities	3,629.70	-98
Payments of Debt Issuance Costs	37.1	0
Statement [Line Items]
Payments on bridge loan	-400	0
Repayments of Senior Debt	-250	0
Proceeds from bridge loan	400	0
Proceeds from Issuance of Other Long-term Debt	1,000	0
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	1	113.5
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	104.7	60.7
Stock compensation	26.3	11.7
Loss on sale of assets	-1.3	-7.1
Accrued interest on zero-coupon subordinated notes	0.5	0.5
Cumulative earnings in excess of distributions from equity method investments	-1.2	-1.3
Asset Impairment Charges	14.8	0
Deferred income taxes	17.4	10.1
Change in assets and liabilities (net of effects of acquisitions):
Increase in accounts receivable (net)	-40.3	-39.2
Increase (Decrease) in Unbilled Receivables	-25.5	0
Increase in inventories	4.2	2.9
Decrease in prepaid expenses and other	-7.7	12.2
Decrease in accounts payable	-48.9	-27.1
Increase (Decrease) in Deferred Revenue	14.1	0
Increase (decrease) in accrued expenses and other	-145	5.4
Net cash provided by operating activities	-86.9	142.3
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	-33.8	-56.5
Proceeds from sale of assets	0.3	0.2
Payments for (Proceeds from) Investments	8	15
Investments in equity affiliates	-3.6	-1.1
Acquisition of businesses, net of cash acquired	-3,622.20	-65.7
Net cash used for investing activities	-3,651.30	-108.1
Effect of exchange rate changes on cash and cash equivalents	-25.1	-1.3
Net increase (decrease) in cash and cash equivalents	-133.6	-65.1
Cash and cash equivalents at beginning of period	580	404
Cash and cash equivalents at end of period	$446.40

BASIS_OF_FINANCIAL_STATEMENT_P

BASIS OF FINANCIAL STATEMENT PRESENTATION	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Financial Statement Presentation	BASIS OF FINANCIAL STATEMENT PRESENTATION
	The condensed consolidated financial statements include the accounts of Laboratory Corporation of America Holdings (the “Company”) and its majority-owned subsidiaries over which it exercises control. Long-term investments in affiliated companies in which the Company exercises significant influence, but which it does not control, are accounted for using the equity method. Investments in which the Company does not exercise significant influence (generally, when the Company has an investment of less than 20% and no representation on the investee’s board of directors) are accounted for using the cost method. All significant inter-company transactions and accounts have been eliminated. The Company does not have any variable interest entities or special purpose entities whose financial results are not included in the condensed consolidated financial statements.
	The financial statements of the Company’s foreign subsidiaries are measured using the local currency as the functional currency. Assets and liabilities are translated at exchange rates as of the balance sheet date. Revenues and expenses are translated at average monthly exchange rates prevailing during the period. Resulting translation adjustments are included in “Accumulated other comprehensive income.”
	The accompanying condensed consolidated financial statements of the Company are unaudited. In the opinion of management, all adjustments necessary for a fair statement of results of operations, cash flows and financial position have been made. Except as otherwise disclosed, all such adjustments are of a normal recurring nature. Interim results are not necessarily indicative of results for a full year. The year-end condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by generally accepted accounting principles.
	Effective as of the first quarter of 2015, the Company changed its operating segments due to a change in its underlying organizational model designed to support the business following the acquisition of Covance Inc. (“Covance” or “the Acquisition”) (see Note 14 - Business Segment Information). The LabCorp Diagnostics (“LCD”) segment includes operations which offer a broad range of clinical laboratory tests and procedures and is comprised of several reporting units based on geography or testing capabilities. The Covance Drug Development (“CDD”) segment includes early drug development services and central labs and clinical trial services. Through these services the Company offers its clients the ability to conduct a variety of studies, in vitro (in test tubes) and in vivo (in animals), to establish the basic pharmacokinetic effect and safety of a drug (preclinical laboratory testing). The central labs and clinical trial services operations includes a full range of clinical and clinical development support services including study design, investigator recruitment, study monitoring, data management, biostatistical analysis, medical writing, regulatory services and preparation and filing of the new drug applications with the appropriate regulatory authorities. The CDD operating segment also offers a wide-range of market access services. The central labs and clinical trials service offerings share the common objectives of demonstrating the clinical effectiveness of a compound, obtaining regulatory approval and maximizing a drug’s commercial potential.
	The condensed consolidated financial statements and notes are presented in accordance with the rules and regulations of the Securities and Exchange Commission and do not contain certain information included in the Company’s 2014 Annual Report on Form 10-K. Therefore, the interim statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report.
	Summary of Significant Accounting Policies
	The following information summarizes the significant accounting policies of the Company's new CDD segment. The significant accounting policies of the LCD segment, which are largely comprised of the historic operations of the Company prior to the Acquisition, have not changed since 2014 and are described in the Company's 2014 Annual Report on Form 10-K.
	Revenue Recognition
	CDD recognizes revenue either as services are performed or products are delivered, depending on the nature of the work contracted. Historically, a majority of CDD’s net revenues have been earned under contracts which range in duration from a few months to two years, but can extend in duration up to five years or longer. CDD also has committed minimum volume arrangements with certain clients with initial terms that generally range in duration from three to ten years. Underlying these arrangements are individual project contracts for the specific services to be provided. These arrangements enable CDD's clients to secure its services in exchange for which they commit to purchase an annual minimum dollar value of services. Under these types of arrangements, if the annual minimum dollar value of service commitment is not reached, the client is required to pay CDD for the shortfall. Progress towards the achievement of annual minimum dollar value of service commitments is monitored throughout the year. Annual minimum commitment shortfalls are not included in net revenues until the amount has been determined and agreed to by the client.
	Service contracts generally take the form of fee-for-service or fixed-price arrangements. In cases where performance spans multiple accounting periods, revenue is recognized as services are performed, measured on a proportional-performance basis, generally using output measures that are specific to the service provided. Examples of output measures in early development service include among others the number of slides read, or specimens prepared for preclinical laboratory services, or number of dosings or number of volunteers enrolled for clinical pharmacology. Examples of output measures in the clinical trials services include among others, number of investigators enrolled, number of sites initiated, number of patients enrolled and number of monitoring visits completed. Revenue is determined by dividing the actual units of work completed by the total units of work required under the contract and multiplying that percentage by the total contract value. The total contract value, or total contractual payments, represents the aggregate contracted price for each of the agreed upon services to be provided. CDD does not have any contractual arrangements spanning multiple accounting periods where revenue is recognized on a proportional-performance basis under which the Company has earned more than an immaterial amount of performance-based revenue (i.e., potential additional revenue tied to specific deliverables or performance). Changes in the scope of work are common, especially under long-term contracts, and generally result in a change in contract value. Once the client has agreed to the changes in scope and renegotiated pricing terms, the contract value is amended with revenue recognized as described above. Estimates of costs to complete are made to provide, where appropriate, for losses expected on contracts. Costs are not deferred in anticipation of contracts being awarded, but instead are expensed as incurred.
	Billing schedules and payment terms are generally negotiated on a contract-by-contract basis. In some cases, CDD bills the client for the total contract value in progress-based installments as certain non-contingent billing milestones are reached over the contract duration, such as, but not limited to, contract signing, initial dosing, investigator site initiation, patient enrollment or database lock. The term “billing milestone” relates only to a billing trigger in a contract whereby amounts become billable and payable in accordance with a negotiated predetermined billing schedule throughout the term of a project. These billing milestones are not performance-based (i.e., there is no potential additional consideration tied to specific deliverables or performance). In other cases, billing and payment terms are tied to the passage of time (e.g., monthly billings). In either case, the total contract value and aggregate amounts billed to the client would be the same at the end of the project. While CDD attempts to negotiate terms that provide for billing and payment of services prior or within close proximity to the provision of services, this is not always possible, and there are fluctuations in the levels of unbilled services and unearned revenue from period to period. While a project is ongoing, cash payments are not necessarily representative of aggregate revenue earned at any particular point in time, as revenues are recognized when services are provided, while amounts billed and paid are in accordance with the negotiated billing and payment terms.
	In some cases, payments received are in excess of revenue recognized. For example, a contract invoicing schedule may provide for an upfront payment of 10% of the full contract value upon contract signing, but at the time of signing performance of services has not yet begun. Payments received in advance of services being provided are deferred as unearned revenue on the balance sheet. As the contracted services are subsequently performed and the associated revenue is recognized, the unearned revenue balance is reduced by the amount of revenue recognized during the period.
	In other cases, services may be provided and revenue recognized before the client is invoiced. In these cases, revenue recognized will exceed amounts billed, and the difference, representing an unbilled receivable, is recorded for the amount that is currently unbillable to the customer pursuant to contractual terms. Once the client is invoiced, the unbilled services are reduced for the amount billed, and a corresponding account receivable is recorded. All unbilled services are billable to customers within one year from the respective balance sheet date.
	Most contracts are terminable with or without cause by the client, either immediately or upon notice. These contracts often require payment to CDD of expenses to wind down the study or project, fees earned to date and, in some cases, a termination fee or a payment to CDD of some portion of the fees or profits that could have been earned by CDD under the contract if it had not been terminated early. Termination fees are included in net revenues when services are performed and realization is assured. In connection with the management of multi-site clinical trials, CDD pays on behalf of its customers fees to investigators, volunteers and other out-of-pocket costs (such as for travel, printing, meetings, couriers, etc.), for which it is reimbursed at cost, without mark-up or profit. Investigator fees are not reflected in total revenues or expenses where CDD acts in the capacity of an agent on behalf of the pharmaceutical company sponsor, passing through these costs without risk or reward to CDD. All other out-of-pocket costs are included in total revenues and expenses.
	Foreign Currencies
	For subsidiaries outside of the United States that operate in a local currency environment, income and expense items are translated to United States dollars at the monthly average rates of exchange prevailing during the period, assets and liabilities are translated at period-end exchange rates and equity accounts are translated at historical exchange rates. Translation adjustments are accumulated in a separate component of shareholders’ equity in the consolidated balance sheets and are included in the determination of comprehensive income in the consolidated statements of comprehensive earnings and consolidated statements of changes in shareholders’ equity. Transaction gains and losses are included in the determination of net income in the consolidated statements of operations.
	Prepaid Expenses and Other Current Assets
	In connection with the management of multi-site clinical trials, CDD pays on behalf of its customers certain out-of-pocket costs, for which the Company is reimbursed at cost, without mark-up or profit. Amounts receivable from customers in connection with such out-of-pocket pass-through costs are included in prepaid expenses and other current assets in the accompanying consolidated balance sheets and totaled $72.4 at March 31, 2015.
	Reimbursable Out-of-Pocket Expenses
	CDD pays on behalf of its customers certain out-of-pocket costs for which the Company is reimbursed at cost, without mark-up or profit. Out-of-pocket costs paid by CDD are reflected in operating expenses, while the reimbursements received are reflected in revenues in the consolidated statements of operations. CDD excludes from revenue and expense in the consolidated statements of operations fees paid to investigators and the associated reimbursement since CDD acts as an agent on behalf of the pharmaceutical company sponsors with regard to investigator payments.
	Cost of Revenue
	Cost of revenue includes direct labor and related benefit charges, other direct costs, shipping and handling fees, and an allocation of facility charges and information technology costs. Selling, general and administrative expenses consist primarily of administrative payroll and related benefit charges, advertising and promotional expenses, administrative travel and an allocation of facility charges and information technology costs. Cost of advertising is expensed as incurred.
	New Accounting Pronouncements
	In April 2014, the FASB issued a new accounting standard on discontinued operations that significantly changes criteria for discontinued operations and disclosures for disposals. Under this new standard, to be a discontinued operation, a component or group of components must represent a strategic shift that has (or will have) a major effect on an entity's operations and financial results. Expanded disclosures for discontinued operations include more details about earnings and balance sheet accounts, total operating and investing cash flows, and cash flows resulting from continuing involvement. The guidance is to be applied prospectively to all new disposals of components and new classifications as held for sale beginning in 2015, with early adoption allowed in 2014. The adoption of this standard is not expected to have a material impact on the consolidated financial statements.
	In May 2014, the FASB issued the converged standard on revenue recognition with the objective of providing a single, comprehensive model for all contracts with customers to improve comparability in the financial statements of companies reporting using International Financial Reporting Standards and U.S. Generally Accepted Accounting Principles. The standard contains principles that an entity must apply to determine the measurement of revenue and timing of when it is recognized. The underlying principle is that an entity must recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. An entity can apply the revenue standard retrospectively to each prior reporting period presented (full retrospective method) or retrospectively with the cumulative effect of initially applying the standard recognized at the date of initial application in retained earnings. As originally issued, the new revenue recognition standard would be effective for the Company beginning January 1, 2017. However, in April, 2015, the FASB voted to propose a one-year deferral of the effective date of the standard. If the proposal is adopted, the standard will be effective for the Company beginning January 1, 2018, with early adoption permitted for annual periods beginning after December 16, 2016. The Company is currently evaluating the expected impact of the standard.
	In August 2014, the FASB issued a new accounting standard that explicitly requires management to assess an entity's ability to continue as a going concern, and to provide related financial statement footnote disclosures in certain circumstances. Under this standard, in connection with each annual and interim period, management must assess whether there is substantial doubt about an entity's ability to continue as a going concern within one year after the financial statements are issued (or available to be issued when applicable). Management shall consider relevant conditions and events that are known and reasonably knowable at such issuance date. Substantial doubt about an entity's ability to continue as a going concern exists if it is probable that the entity will be unable to meet its obligations as they become due within one year after issuance date. Disclosures will be required if conditions or events give rise to substantial doubt. This standard is effective for the Company for the annual period ending after December 15, 2016, with early adoption permitted. The adoption of this standard is not expected to have a material impact on the consolidated financial statements.
	In April 2015, the FASB issued an update which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the associated debt liability. This standard is effective for the Company beginning January 1, 2016. The new guidance will be applied on a retrospective basis. The adoption of this standard is not expected to have a material impact on the consolidated financial statements.

EARNINGS_PER_SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE
	Basic earnings per share is computed by dividing net earnings attributable to Laboratory Corporation of America Holdings by the weighted average number of common shares outstanding. Diluted earnings per share is computed by dividing net earnings including the impact of dilutive adjustments by the weighted average number of common shares outstanding plus potentially dilutive shares, as if they had been issued at the earlier of the date of issuance or the beginning of the period presented. Potentially dilutive common shares result primarily from the Company’s outstanding stock options, restricted stock awards, restricted stock units, performance share awards, and shares issuable upon conversion of zero-coupon subordinated notes.
	The following represents a reconciliation of basic earnings per share to diluted earnings per share:
		Three Months Ended March 31,
		2015						2014
		Earnings			Shares	Per		Earnings		Shares	Per
						Share					Share
						Amount					Amount
	Basic earnings per share:
	Net earnings	$	0.7		91.9	$	0.01	$	113.1	85.2	$	1.33
	Dilutive effect of employee stock options and awards	—			1.2			—		0.9
	Effect of convertible debt	—			0.7			—		0.5
	Diluted earnings per share:
	Net earnings including impact of dilutive adjustments	$	0.7		93.8	$	0.01	$	113.1	86.6	$	1.31
	The following table summarizes the potential common shares not included in the computation of diluted earnings per share because their impact would have been antidilutive:
		Three Months Ended March 31,
		2015		2014
	Stock options	—		—

RESTRUCTURING_AND_OTHER_SPECIA

RESTRUCTURING AND OTHER SPECIAL CHARGES	3 Months Ended
	Mar. 31, 2015
Restructuring and Related Activities [Abstract]
Restructuring and Other Special Charges	RESTRUCTURING AND OTHER SPECIAL CHARGES
	During the first three months of 2015, the Company recorded net restructuring and other special charges of $19.3. The charges were comprised of $3.2 related to severance and other personnel costs along with $16.1 in costs associated with facility closures and impairment of certain information technology assets.
	In addition, during the first three months of 2015, the Company recorded $6.0 in consulting expenses (recorded in selling, general and administrative expenses) relating to fees incurred as part of its business process improvement initiative (“Project LaunchPad”). The Company also recorded $166.0 of deal costs related to the Acquisition, of which $80.6 is included in selling, general and administrative expenses, $32.8 is included in cost of revenue, and $52.6 is included in interest expense.
	During the first three months of 2014, the Company recorded net restructuring and other special charges of $7.6. The charges were comprised of $2.8 related to severance and other personnel costs along with $4.9 in costs associated with facility closures and general integration initiatives. These charges were offset by the reversal of previously established reserves of $0.1 in unused severance.
	The following represents the Company’s restructuring reserve activities for the period indicated:
		Severance			Lease			Total
		and Other			and Other
		Employee			Facility
		Costs			Costs
	Balance as of December 31, 2014	$	0.4		$	21.7		$	22.1
	Restructuring charges	3.2			16.1			19.3
	Reduction of prior restructuring accruals	—			—			—
	Cash payments and other adjustments	(2.9		)	(17.0		)	(19.9		)
	Balance as of March 31, 2015	$	0.7		$	20.8		$	21.5
	Current							$	7.5
	Non-current							14
								$	21.5
		Severance			Lease			Total
		and Other			and Other
		Employee			Facility
		Costs			Costs
	Balance as of December 31, 2014	$	0.4		$	21.7		$	22.1
	Restructuring charges	3.2			16.1			19.3
	Reduction of prior restructuring accruals	—			—			—
	Cash payments and other adjustments	(2.9		)	(17.0		)	(19.9		)
	Balance as of March 31, 2015	$	0.7		$	20.8		$	21.5
	Current							$	7.5
	Non-current							14
								$	21.5

GOODWILL_AND_INTANGIBLE_ASSETS

GOODWILL AND INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS
	As of March 31, 2015, the Company has recorded goodwill of $6,282.2, which includes a preliminary goodwill balance of $3,176.1 related to the Acquisition. Effective in the first quarter of 2015, the Company changed its operating segments due to a change in its underlying organizational model designed to support the business following the Acquisition (see Note 14 - Business Segment Information). The Company did not operate under the realigned operating segment structure prior to the first quarter of 2015. This change in segments resulted in a reassignment of goodwill of approximately $110.5 among some of the Company’s reportable segments (and reporting units) based on relative fair value. Prior period information has been retrospectively adjusted to reflect this reassignment.
	The following is a summary of the Company’s goodwill by reportable segment, reflecting the retrospective reassignment as of December 31, 2014:
	LCD	$	2,988.90
	CDD	110.5
		$	3,099.40
	During the first quarter of 2015, the Company recorded additional goodwill of $3,176.1 related to the Acquisition. The Company has preliminarily assigned the assets and liabilities acquired. The Company intends to finalize the assignment of the goodwill from the Acquisition during 2015 and could be substantially complete in the second quarter.
	The changes in the carrying amount of goodwill for the three month period ended March 31, 2015 and for the year ended December 31, 2014 are as follows:
		LCD						CDD				Total
		March 31,			December 31, 2014			March 31,		December 31, 2014		March 31,			December 31, 2014
		2015						2015				2015
	Balance as of January 1	$	2,988.90		$	2,912.30		$	110.5	$	110.5	$	3,099.40		$	3,022.80
	Goodwill acquired during the period	11.5			81.8			3,176.10		—		3,187.60			81.8
	Adjustments to goodwill	(4.8		)	(5.2		)	—		—		(4.8		)	(5.2		)
	Balance at end of period	$	2,995.60		$	2,988.90		$	3,286.60	$	110.5	$	6,282.20		$	3,099.40
	The components of identifiable intangible assets are as follows:
		March 31, 2015								December 31, 2014
		Gross			Accumulated			Net		Gross		Accumulated			Net
		Carrying			Amortization					Carrying		Amortization
		Amount								Amount
	Customer relationships	$	3,281.00		$	(630.1	)	$	2,650.90	$	1,361.60	$	(606.8	)	$	754.8
	Patents, licenses and technology	122.2			(98.4		)	23.8		125.9		(95.9		)	30
	Non-compete agreements	46.1			(33.2		)	12.9		45.6		(31.7		)	13.9
	Trade names	424.3			(95.8		)	328.5		133.3		(91.6		)	41.7
	Land use right	4.9			(0.2		)	4.7		—		—			—
	Canadian licenses	582.5			—			582.5		635.4		—			635.4
		$	4,461.00		$	(857.7	)	$	3,603.30	$	2,301.80	$	(826.0	)	$	1,475.80
	Amortization of intangible assets for the three month periods ended March 31, 2015 and March 31, 2014 was $31.4 and $21.0, respectively. Amortization expense for the net carrying amount of intangible assets is estimated to be $132.8 for the remainder of fiscal 2015, $171.4 in fiscal 2016, $164.2 in fiscal 2017, $152.2 in fiscal 2018, $145.2 in fiscal 2019 and $2,239.8 thereafter.

DEBT

DEBT	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Debt	DEBT
	Short-term borrowings and the current portion of long-term debt at March 31, 2015 and December 31, 2014 consisted of the following:
		March 31,		December 31, 2014
		2015
	Zero-coupon convertible subordinated notes	$	94.4	$	93.9
	5.625% senior notes due 2015	250		250
	Current portion of capital leases	4.2		3.2
	Total short-term borrowings and current portion of long-term debt	$	348.6	$	347.1
	Long-term debt at March 31, 2015 and December 31, 2014 consisted of the following:
		March 31,		December 31, 2014
		2015
	3.125% senior notes due 2016	$	325	$	325
	2.20% senior notes due 2017	500		500
	2.50% senior notes due 2018	400		400
	4.625% senior notes due 2020	634		618.5
	2.625% senior notes due 2020	500		—
	3.75% senior notes due 2022	500		500
	3.20% senior notes due 2022	500		—
	4.00% senior notes due 2023	300		300
	3.60% senior notes due 2025	1,000.00		—
	4.70% senior notes due 2045	900		—
	Revolving credit facility	60		—
	Term loan	925		—
	Capital leases	53.7		39.2
	Total long-term debt	$	6,597.70	$	2,682.70
	Senior Notes
	As a result of the Acquisition, the Company assumed privately placed senior notes in an aggregate principal amount of $250.0 issued pursuant to a Note Purchase Agreement dated October 2, 2013. On March 5, 2015, the Company caused Covance to prepay all of the outstanding Senior Notes at 100 percent of the principal amount plus accrued interest, and a total make-whole amount of $37.4 which was expensed. The Note Purchase Agreement terminated effective March 5, 2015 in connection with the prepayment of the Senior Notes.
	During the third quarter of 2013, the Company entered into two fixed-to-variable interest rate swap agreements for its 4.625% senior notes due 2020 with an aggregate notional amount of $600.0 and variable interest rates based on one-month LIBOR plus 2.298% to hedge against changes in the fair value of a portion of the Company's long term debt.  These derivative financial instruments are accounted for as fair value hedges of the senior notes due 2020.  These interest rate swaps are included in other long term assets and added to the value of the senior notes, with an aggregate fair value of $34.0 at March 31, 2015.
	Zero-Coupon Subordinated Notes
	On March 11, 2015, the Company announced that for the period from March 12, 2015 to September 11, 2015, the zero-coupon subordinated notes will accrue contingent cash interest at a rate of no less than 0.125% of the average market price of a zero-coupon subordinated note for the five trading days ended March 6, 2015, in addition to the continued accrual of the original issue discount.
	On April 1, 2015, the Company announced that its zero-coupon subordinated notes may be converted into cash and common stock at the conversion rate of 13.4108 per $1,000.0. principal amount at maturity of the notes, subject to the terms of the zero-coupon subordinated notes and the Indenture, dated as of October 24, 2006 between the Company and The Bank of New York Mellon, as trustee and the conversion agent. In order to exercise the option to convert all or a portion of the zero-coupon subordinated notes, holders are required to validly surrender their zero-coupon subordinated notes at any time during the calendar quarter beginning April 1, 2015, through the close of business on the last business day of the calendar quarter, which is 5:00 p.m., New York City time, on Tuesday, June 30, 2015. If notices of conversion are received, the Company plans to settle the cash portion of the conversion obligation (i.e. the accreted principal amount of the securities to be converted) with cash on hand and/or borrowings under its revolving credit facility. The remaining amount, if any, will be settled with shares of common stock.
	Credit Facilities
	On November 2, 2014, in connection with entering into the Merger Agreement with Covance, the Company entered into a bridge facility commitment letter. Under the bridge facility commitment letter, the lenders agreed to provide a $4,250.0 senior unsecured bridge term loan credit facility which consisted of a $3,850.0 364-day unsecured debt bridge tranche and a $400.0 60-day unsecured cash bridge tranche for the purpose of financing all or a portion of the cash consideration and the fees and expenses in connection with the transactions contemplated by the Merger Agreement. The bridge facility was permitted to be drawn only in a single drawing on the closing date of the Acquisition.
	On December 19, 2014, the Company entered into a five-year term loan credit facility in the principal amount of $1,000.0 for the purpose of financing a portion of the cash consideration and the fees and expenses in connection with the Acquisition. Pursuant to the bridge facility commitment letter, upon the Company’s entry into the term loan credit facility, the $4,250.0 bridge facility was reduced to a $3,250.0 commitment, comprising a $2,850.0 364-day unsecured debt bridge tranche and a $400.0 60-day cash bridge tranche. The $1,000.0 of term loan commitments made under the term loan credit facility reduced the debt bridge tranche under the bridge facility dollar for dollar.
	The term loan credit facility was advanced in full on February 19, 2015, the date of the Company’s completion of the Acquisition. The term loan credit facility will mature five years after the closing date of the Acquisition and may be prepaid without penalty. The term loan balance at March 31, 2015 was $925.0.
	On December 19, 2014, the Company also entered into an amendment and restatement of its existing senior revolving credit facility, which was originally entered into on December 21, 2011. The senior revolving credit facility consists of a five-year revolving facility in the principal amount of up to $1,000.0, with the option of increasing the facility by up to an additional $250.0, subject to the agreement of one or more new or existing lenders to provide such additional amounts and certain other customary conditions. The new revolving credit facility also provides for a subfacility of up to $100.0 for swing line borrowings and a subfacility of up to $125.0 for issuances of letters of credit. The new revolving credit facility is permitted to be used for general corporate purposes, including working capital, capital expenditures, funding of share repurchases and certain other payments, and acquisitions and other investments. There was $60.0 and $0.0 outstanding on the Company's revolving credit facility at March 31, 2015 and December 31, 2014, respectively.
	On January 30, 2015, the Company issued the Acquisition Notes, which represent $2,900.0 in debt securities consisting of $500.0 aggregate principal amount of 2.625% Senior Notes due 2020, $500.0 aggregate principal amount of 3.20% Senior Notes due 2022, $1,000.0 aggregate principal amount of 3.60% Senior Notes due 2025 and $900.0 aggregate principal amount of 4.70% Senior Notes due 2045. Net proceeds from the offering of the Acquisition Notes were $2,870.2 after deducting underwriting discounts and other estimated expenses of the offering. Net proceeds were used to pay a portion of the cash consideration and the fees and expenses in connection with the Acquisition. Pursuant to the bridge facility commitment letter, upon the Company’s issuance of the Acquisition Notes the remaining $2,850.0 364-day unsecured debt bridge tranche under the senior unsecured bridge term loan credit facility was terminated.
	On February 13, 2015, the Company entered into a 60-day cash bridge term loan credit facility in the principal amount of $400.0 for the purpose of financing a portion of the cash consideration and the fees and expenses in connection with the Acquisition. The 60-day cash bridge term loan credit facility was entered into on the terms set forth in the bridge facility commitment letter for the $400.0 60-day cash bridge tranche. The 60-day cash bridge term loan credit facility was advanced in full on February 19, 2015, the date of the Company’s completion of the Acquisition. On March 16, 2015, the Company elected to prepay the bridge facility without penalty.
	Under the term loan facility and the revolving credit facility, the Company is subject to negative covenants limiting subsidiary indebtedness and certain other covenants typical for investment grade-rated borrowers, and the Company is required to maintain a leverage ratio that declines over time. Prior to the Acquisition closing date, the leverage ratio was required to have been no greater than 3.75 to 1.0 calculated by excluding the $2,900.0 in Acquisition Notes. From and after the Acquisition closing date, the leverage ratio must be no greater than 4.75 to 1.0 with respect to the last day of each of the first four fiscal quarters ending on or after the closing date, 4.25 to 1.0 with respect to the last day of each of the fifth through eighth fiscal quarters ending after the closing date, and 3.75 to 1.0 with respect to the last day of each fiscal quarter ending thereafter. The Company was in compliance with all covenants in the term loan facility and the new revolving credit facility at March 31, 2015. As of March 31, 2015, the ratio of total debt to consolidated last twelve months EBITDA was 4.2 to 1.0.
	The term loan credit facility accrues interest at a per annum rate equal to, at the Company’s election, either a LIBOR rate plus a margin ranging from 1.125% to 2.00%, or a base rate determined according to a prime rate or federal funds rate plus a margin ranging from 0.125% to 1.00%. Advances under the revolving credit facility will accrue interest at a per annum rate equal to, at the Company’s election, either a LIBOR rate plus a margin ranging from 1.00% to 1.60%, or a base rate determined according to a prime rate or federal funds rate plus a margin ranging from 0.00% to 0.60%. Fees are payable on outstanding letters of credit under the new revolving credit facility at a per annum rate equal to the applicable margin for LIBOR loans, and the Company is required to pay a facility fee on the aggregate commitments under the new revolving credit facility, at a per annum rate ranging from 0.125% to 0.40%. The interest margin applicable to the credit facilities, and the facility fee and letter of credit fees payable under the new revolving credit facility, are based on the Company’s senior credit ratings as determined by Standard & Poor’s and Moody’s, which are currently BBB and Baa2, respectively.
	As of March 31, 2015, the effective interest rate on the revolving credit facility was 1.28% and the effective interest rate on the term loan was 1.47%.

PREFERRED_STOCK_AND_COMMON_SHA

PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity Note [Abstract]
Preferred Stock and Common Shareholders' Equity	. PREFERRED STOCK AND COMMON SHAREHOLDERS’ EQUITY
	The Company is authorized to issue up to 265.0 shares of common stock, par value $0.10 per share. The Company’s treasury shares are recorded at aggregate cost. The Company is authorized to issue up to 30.0 shares of preferred stock, par value $0.10 per share. There were no preferred shares outstanding as of March 31, 2015.
	The changes in common shares issued and held in treasury are summarized below:
		Issued			Held in			Outstanding
					Treasury
	Common shares at December 31, 2014	107.1			(22.5	)		84.6
	Common stock issued in conjunction with the Acquisition	15.3			—			15.3
	Common stock issued under employee stock plans	0.6			—			0.6
	Common shares at March 31, 2015	123			(22.5	)		100.5
	Share Repurchase Program
	As of March 31, 2015 and December 31, 2014, the Company had outstanding authorization from the Board of Directors to purchase up to $789.5 of Company common stock based on settled trades as of these respective dates. The repurchase authorization has no expiration date. Following the announcement of the Acquisition, the Company suspended its share repurchases. The Company does not anticipate resuming its share repurchase activity until it reaches its targeted ratio of total debt to consolidated EBITDA of 2.5 to 1.0.
	Accumulated Other Comprehensive Earnings
	The components of accumulated other comprehensive earnings are as follows:
		Foreign				Net			Unrealized Gains and Losses on Available for Sale Securities			Accumulated
		Currency				Benefit						Other
		Translation				Plan						Comprehensive
		Adjustments				Adjustments						Earnings
	Balance at December 31, 2014	$	68			$	(78.6	)	$	0.1		$	(10.5	)
	Other comprehensive earnings before reclassifications	(168.5		)		1.2			(0.1		)	(167.4		)
	Amounts reclassified from accumulated other comprehensive earnings to the Condensed Consolidated Statement of Operations (a)	—				(0.3		)	—			(0.3		)
	Tax effect of adjustments	47.4				(0.3		)	—			47.1
	Balance at March 31, 2015	$	(53.1	)		$	(78.0	)	$	—		$	(131.1	)
	(a) The amortization of prior service cost is included in the computation of net periodic benefit cost. See Note 10 (Pension and Post-retirement Plans) below for additional information regarding the Company's net periodic benefit cost.

INCOME_TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES
	The Company does not recognize a tax benefit unless the Company concludes that it is more likely than not that the benefit will be sustained on audit by the taxing authority based solely on the technical merits of the associated tax position. If the recognition threshold is met, the Company recognizes a tax benefit measured at the largest amount of the tax benefit that the Company believes is greater than 50% likely to be realized.
	The gross unrecognized income tax benefits were $28.6 and $16.7 at March 31, 2015 and December 31, 2014, respectively. Substantially all of the increase relates to matters assumed associated with the Acquisition. It is anticipated that the amount of the unrecognized income tax benefits will change within the next twelve months; however, these changes are not expected to have a significant impact on the results of operations, cash flows or the financial position of the Company.
	As of March 31, 2015 and December 31, 2014, $28.6 and $16.7, respectively, are the approximate amounts of gross unrecognized income tax benefits that, if recognized, would favorably affect the effective income tax rate in future periods. Substantially all of the increase relates to matters assumed associated with the Acquisition.
	The Company recognizes interest and penalties related to unrecognized income tax benefits in income tax expense. Accrued interest and penalties related to uncertain tax positions totaled $9.6 and $8.2 as of March 31, 2015 and December 31, 2014, respectively. The transfer of Covance's beginning balances accounted for substantially all of the increase.
	The valuation allowance provided as a reserve against certain deferred tax assets is $16.8 and $17.1 as of March 31, 2015 and December 31, 2014, respectively.
	The Company has substantially concluded all U.S. federal income tax matters for years through 2011. Substantially all material state and local, and foreign income tax matters have been concluded through 2007 and 2001, respectively.
	The Company has various state and international income tax examinations ongoing throughout the year.  Management believes adequate provisions have been recorded related to all open tax years.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES
	The Company is involved from time to time in various claims and legal actions, including arbitrations, class actions, and other litigation (including those described in more detail below), arising in the ordinary course of business. Some of these actions involve claims that are substantial in amount. These matters include, but are not limited to, intellectual property disputes, professional liability, employee-related matters, and inquiries, including subpoenas and other civil investigative demands, from governmental agencies and Medicare or Medicaid payers and managed care payers reviewing billing practices or requesting comment on allegations of billing irregularities that are brought to their attention through billing audits or third parties. The Company receives civil investigative demands or other inquiries from various governmental bodies in the ordinary course of its business. Such inquiries can relate to the Company or other health care providers. The Company works cooperatively to respond to appropriate requests for information.
	The Company is also named from time to time in suits brought under the qui tam provisions of the False Claims Act and comparable state laws. These suits typically allege that the Company has made false statements and/or certifications in connection with claims for payment from federal or state health care programs. The suits may remain under seal (hence, unknown to the Company) for some time while the government decides whether to intervene on behalf of the qui tam plaintiff. Such claims are an inevitable part of doing business in the health care field today.
	The Company believes that it is in compliance in all material respects with all statutes, regulations and other requirements applicable to its clinical laboratory operations and drug development support services. The health care diagnostics and drug development industries are, however, subject to extensive regulation, and the courts have not interpreted many of the applicable statutes and regulations. There can be no assurance, therefore, that the applicable statutes and regulations will not be interpreted or applied by a prosecutorial, regulatory or judicial authority in a manner that would adversely affect the Company. Potential sanctions for violation of these statutes and regulations include significant fines, the loss of various licenses, certificates and authorizations, and/or exclusion from participation in government programs.
	Many of the current claims and legal actions against the Company are in preliminary stages, and many of these cases seek an indeterminate amount of damages. The Company records an aggregate legal reserve, which is determined using actuarial calculations based on historical loss rates and assessment of trends experienced in settlements and defense costs. In accordance with FASB Accounting Standards Codification Topic 450, “Contingencies”, the Company establishes reserves for judicial, regulatory, and arbitration matters outside the aggregate legal reserve if and when those matters present loss contingencies that are both probable and estimable and would exceed the aggregate legal reserve. When loss contingencies are not both probable and estimable, the Company does not establish separate reserves.
	The Company is unable to estimate a range of reasonably probable loss for the proceedings described in more detail below in which damages either have not been specified or, in the Company's judgment, are unsupported and/or exaggerated and (i) the proceedings are in early stages; (ii) there is uncertainty as to the outcome of pending appeals or motions; (iii) there are significant factual issues to be resolved; and/or (iv) there are novel legal issues to be presented. For these proceedings, however, the Company does not believe, based on currently available information, that the outcomes will have a material adverse effect on the Company's financial condition, the outcomes could be material to the Company's operating results for any particular period, depending, in part, upon the operating results for such period.
	As reported, the Company reached a settlement in the previously disclosed lawsuit, California ex rel. Hunter Laboratories, LLC et al. v. Quest Diagnostics Incorporated, et al. (“Hunter Labs Settlement Agreement”), to avoid the uncertainty and costs associated with prolonged litigation. Pursuant to the executed settlement agreement, the Company recorded a litigation settlement expense of $34.5 in the second quarter of 2011 (net of a previously recorded reserve of $15.0) and paid the settlement amount of $49.5 in the third quarter of 2011. The Company also agreed to certain reporting obligations regarding its pricing for a limited time period and, at the option of the Company in lieu of such reporting obligations, to provide Medi-Cal with a discount from Medi-Cal's otherwise applicable maximum reimbursement rate from November 1, 2011, through October 31, 2012. In June of 2012, the California legislature enacted Assembly Bill No. 1494, Section 9 of which directs the Department of Health Care Services ("DHCS") to establish new reimbursement rates for Medi-Cal clinical laboratory services that will be based on payments made to California clinical laboratories for similar services by other third-party payers. With stakeholder input, DHCS established data elements and a format for laboratories to report payment data from comparable third-party payers. Laboratories reported payment data to DHCS in the summer of 2013. On March 28, 2014, Assembly Bill No. 1124 extended the implementation deadline of new regulations until June 30, 2016. Assembly Bill No. 1494 provides that until the new rates are set through this process, Medi-Cal payments for clinical laboratory services will be reduced (in addition to a 10.0% payment reduction imposed by Assembly Bill No. 97 in 2011) by “up to 10 percent” for tests with dates of service on or after July 1, 2012, with a cap on payments set at 80.0% of the lowest maximum allowance established under the federal Medicare program. Under the terms of the Hunter Labs Settlement Agreement, the enactment of this California legislation terminates the Company's reporting obligations (or obligation to provide a discount in lieu of reporting) under that agreement. In December 2014, DHCS announced at a stakeholder meeting the results of its analysis of payment data reported by laboratories in 2013 and its proposed rate methodology, on which it solicited stakeholder comments. The Company objected to the proposal by DHCS to exclude from the new rate calculations data on payments from comparable third-party payers exceeding 80.0% of Medicare reimbursement amounts and its proposal to impose the 10.0% payment reduction enacted in Assembly Bill No. 97 after calculation of the new rates. In January of 2015, after receiving stakeholder comments, DHCS instructed laboratories to submit 2014 payment data by March 27, 2015, which DHCS will use (except for data on payment amounts exceeding 80.0% of Medicare reimbursement) to establish new rates effective July 1, 2015, to which DHCS intends to apply the 10.0% payment reduction referenced in Assembly Bill No. 97. While the Company continues to dispute this methodology, taken together, these changes are not expected to have a material impact on the Company's consolidated revenues or results of operations.
	As previously reported, the Company responded to an October 2007 subpoena from the United States Department of Health & Human Services Office of Inspector General's regional office in New York. On August 17, 2011, the Southern District of New York unsealed a False Claims Act lawsuit, United States of America ex rel. NPT Associates v. Laboratory Corporation of America Holdings, which alleges that the Company offered UnitedHealthcare kickbacks in the form of discounts in return for Medicare business. The Plaintiff's third amended complaint further alleges that the Company's billing practices violated the false claims acts of fourteen states and the District of Columbia. The lawsuit seeks actual and treble damages and civil penalties for each alleged false claim, as well as recovery of costs, attorney's fees, and legal expenses. Neither the United States government nor any state government has intervened in the lawsuit. The Company's Motion to Dismiss was granted in October 2014. The Company intends to vigorously defend the lawsuit should it proceed further.
	In addition, the Company has received various other subpoenas since 2007 related to Medicaid billing. In October 2009, the Company received a subpoena from the State of Michigan Department of Attorney General seeking documents related to its billing to Michigan Medicaid. In June 2010, the Company received a subpoena from the State of Florida Office of the Attorney General requesting documents related to its billing to Florida Medicaid. In October 2013, the Company received a civil investigative demand from the State of Texas Office of the Attorney General requesting documents related to its billing to Texas Medicaid. The Company is cooperating with these requests.
	On November 4, 2013, the State of Florida through the Office of the Attorney General filed an Intervention Complaint in a False Claims Act lawsuit, State of Florida ex rel. Hunter Laboratories, LLC and Chris Riedel v. Quest Diagnostics Incorporated, et al. in the Circuit Court for the Second Judicial Circuit for Leon County. The complaint, originally filed by a competitor laboratory, alleges that the Company overcharged Florida’s Medicaid program. The lawsuit seeks actual and treble damages and civil penalties for each alleged false claim, as well as recovery of costs, attorney’s fees, and legal expenses. On January 3, 2014, the Company filed a Petition for the Administrative Determination of the Invalidity of an Existing Rule against the Agency for Health Care Administration (“AHCA”). The Petition sought the invalidity of Rule 59G-5.110(2) of the Florida Administrative Code, which was relied upon by the Attorney General in its Intervention Complaint. On March 28, 2014, an Administrative Law Judge for the State of Florida Division of Administrative Hearings issued an order finding that Rule 59G-5.110(2) of the Florida Administrative Code was invalid. In the interim, the Attorney General filed a First Amended Intervention Complaint on January 30, 2014, which seeks actual and treble damages and civil penalties for alleged false claims, as well as recovery of costs, attorney's fees, and legal expenses, for allegedly overcharging Florida's Medicaid program. The Company's Motion to Dismiss was denied in February 2015. The Company will vigorously defend the lawsuit.
	On May 2, 2013, the Company was served with a False Claims Act lawsuit, State of Georgia ex rel. Hunter Laboratories, LLC and Chris Riedel v. Quest Diagnostics Incorporated, et al., filed in the State Court of Fulton County, Georgia. The lawsuit, filed by a competitor laboratory, alleges that the Company overcharged Georgia's Medicaid program. The case was removed to the United States District Court for the Northern District of Georgia. The lawsuit seeks actual and treble damages and civil penalties for each alleged false claim, as well as recovery of costs, attorney's fees, and legal expenses. The government filed a notice declining to intervene in the case. On March 14, 2014, the Company's Motion to Dismiss was granted. The Plaintiffs' motion seeking leave to replead their complaint was granted and the Company's Motion to Dismiss the First Amended Complaint is pending. The Company will vigorously defend the lawsuit.
	In October 2011, a putative stockholder of the Company made a letter demand through his counsel for inspection of documents related to policies and procedures concerning the Company's Board of Directors' oversight and monitoring of the Company's billing and claim submission process. The letter sought documents prepared for or by the Board regarding allegations from the California ex rel. Hunter Laboratories, LLC et al. v. Quest Diagnostics Incorporated, et al., lawsuit and documents reviewed and relied upon by the Board in connection with the settlement of that lawsuit. The Company responded to the request pursuant to Delaware law.
	On November 18, 2011, the Company received a letter from United States Senators Baucus and Grassley requesting information regarding the Company's relationships with its largest managed care customers. The letter requested information about the Company's contracts and financial data regarding its managed care customers. Company representatives met with Senate Finance Committee staff after receiving the request and subsequently produced documents in response. The Company continues to cooperate with the request for information.
	On February 27, 2012, the Company was served with a False Claims Act lawsuit, United States ex rel. Margaret Brown v. Laboratory Corporation of America Holdings and Tri-State Clinical Laboratory Services, LLC, filed in the United States District Court for the Southern District of Ohio, Western Division. The Company owned 50% of Tri-State Clinical Laboratory Services, LLC, which was dissolved in June of 2011 pursuant to a voluntary petition under Chapter 7 of Title 11 of the United States Code. The lawsuit alleges that the defendants submitted false claims for payment for laboratory testing services performed as a result of financial relationships that violated the federal Stark and Anti-Kickback laws. The lawsuit seeks actual and treble damages and civil penalties for each alleged false claim, as well as recovery of costs, attorney's fees, and legal expenses. The United States government has not intervened in the lawsuit. The parties have reached a settlement in principle, but the Company will vigorously defend the lawsuit if the settlement is not finalized.
	On June 7, 2012, the Company was served with a putative class action lawsuit, Yvonne Jansky v. Laboratory Corporation of America, et al., filed in the Superior Court of the State of California, County of San Francisco. The complaint alleges that the Defendants committed unlawful and unfair business practices, and violated various other state laws by changing screening codes to diagnostic codes on laboratory test orders, thereby resulting in customers being responsible for co-payments and other debts. The lawsuit seeks injunctive relief, actual and punitive damages, as well as recovery of attorney's fees, and legal expenses. The Company will vigorously defend the lawsuit.
	On August 24, 2012, the Company was served with a putative class action lawsuit, Sandusky Wellness Center, LLC, et al. v. MEDTOX Scientific, Inc., et al., filed in the United States District Court for the District of Minnesota. The lawsuit alleges that on or about February 21, 2012, the defendants violated the federal Telephone Consumer Protection Act ("TCPA") by sending unsolicited facsimiles to Plaintiff and more than 39 other recipients without the recipients' prior express permission or invitation. The lawsuit seeks the greater of actual damages or the sum of $0.0005 for each violation, subject to trebling under the TCPA, and injunctive relief. In September 2014, Plaintiff's Motion for class certification was denied. In January of 2015, the Company’s Motion for Summary Judgment on the remaining individual claim was granted. Plaintiff has filed a notice of appeal. The Company will vigorously defend the lawsuit.
	The Company was a defendant in two separate putative class action lawsuits, Christine Bohlander v. Laboratory Corporation of America, et al., and Jemuel Andres, et al. v. Laboratory Corporation of America Holdings, et al., related to overtime pay. After the filing of the two lawsuits on July 8, 2013, the Bohlander lawsuit was consolidated into the Andres lawsuit, and the consolidated lawsuit is now pending in the Superior Court of California for the County of Los Angeles. In the consolidated lawsuit, the Plaintiffs allege on behalf of similarly situated phlebotomists and couriers that the Company failed to pay overtime, failed to provide meal and rest breaks, and committed other violations of the California Labor Code. The complaint seeks monetary damages, civil penalties, costs, injunctive relief, and attorney's fees. The parties have reached a tentative class settlement, which is subject to Court approval. The Court held a hearing on the merits of the settlement terms on February 26, 2015 and requested further briefing on the settlement terms. Another hearing is scheduled for May 14, 2015. The Company will vigorously defend the lawsuit.
	The Company is also a defendant in two additional putative class action lawsuits alleging similar claims to the Bohlander/Andres consolidated lawsuit. The lawsuit Rachel Rabanes v. California Laboratory Sciences, LLC, et al., was filed in April 2014 in the Superior Court of California for the County of Los Angeles, and the lawsuit Rita Varsam v. Laboratory Corporation of America DBA LabCorp, was filed in June 2014 in the Superior Court of California for the County of San Diego. In these lawsuits, the Plaintiffs allege on behalf of similarly situated employees that the Company failed to pay overtime, failed to provide meal and rest breaks, and committed other violations of the California Labor Code. The complaints seek monetary damages, civil penalties, costs, injunctive relief, and attorney's fees. The Company will vigorously defend these lawsuits.
	On December 17, 2010, the Company was served with a lawsuit, Oliver Wuth, et al. v. Laboratory Corporation of America, et al., filed in the State Superior Court of King County, Washington. The lawsuit alleges that the Company was negligent in the handling of a prenatal genetic test order that allegedly resulted in the parents being given incorrect information. The matter was tried to a jury beginning on October 21, 2013. On December 10, 2013, the jury returned a verdict in in Plaintiffs’ favor in the amount of $50.0, with 50.0% of liability apportioned to the Company and 50.0% of liability apportioned to co-Defendant Valley Medical Center. The Company filed post-judgment motions for a new trial, which were denied, and is vigorously pursuing an appeal of the judgment on multiple grounds. The Company carries self-insurance reserves and excess liability insurance sufficient to cover the potential liability in this case.
	On July 3, 2012, the Company was served with a lawsuit, John Wisekal, as Personal Representative of the Estate of Darien Wisekal v. Laboratory Corporation of America Holdings and Glenda C. Mixon, filed in the Circuit Court of the Fifteenth Judicial Circuit in and for Palm Beach County, Florida. The lawsuit alleges that the Company misread a Pap test. The case was removed to the United States District Court for the Southern District of Florida. The matter was tried to a jury beginning on April 1, 2014. On April 17, 2014, the jury returned a verdict in Plaintiff’s favor in the amount of $20.8, with non-economic damages reduced by 25% to account for the Plaintiff's negligence, for a final verdict of $15.8. The Company filed post-trial motions. On July 28, 2014, the Court granted the Company’s motion for remittitur and reduced the jury’s non-economic damages award to $5.0, reduced by 25.0% for the Plaintiff’s negligence. Accordingly, the total judgment is $4.4. In December 2014, the Court granted Plaintiff's Motion to Certify the remittitur order for interlocutory appeal and stayed the case pending the Eleventh Circuit Court of Appeal's review of the Plaintiff's challenge to the reduction in judgment.
	On July 9, 2014, the Company was served with a putative class action lawsuit, Christopher W. Legg, et al. v. Laboratory Corporation of America, filed in the United States District Court for the Southern District of Florida. The complaint alleges that the Company willfully violated the Fair and Accurate Credit Transactions Act by allegedly providing credit card expiration date information on an electronically printed credit card receipt. The lawsuit seeks damages of not less than $0.0001 but not more than $0.01 per violation, and punitive damages, injunctive relief, and attorney’s fees. The Company will vigorously defend the lawsuit.
	Prior to the consummation of the Company’s acquisition of LipoScience, Inc., purported stockholders of LipoScience filed four putative class action lawsuits against LipoScience, members of the LipoScience board of directors, the Company and Bear Acquisition Corp., a wholly owned subsidiary of the Company, in the Delaware Court of Chancery and, with respect to one of the lawsuits, in the Superior Court of Wake County, North Carolina. The lawsuits alleged breach of fiduciary duty and/or other violations of state law arising out of the proposed acquisition. Each suit sought, among other things, injunctive relief enjoining the merger. On October 23, 2014, the case in North Carolina was voluntarily dismissed without prejudice by the Plaintiff. On October 29, 2014, the Delaware Court of Chancery consolidated the four actions under the caption In re LipoScience, Inc. Stockholder Litigation, Consolidated C.A. No. 10252-VCP (the “Consolidated Action”). On November 7, 2014, the Consolidated Action plaintiffs entered into a memorandum of understanding with the defendants regarding a settlement of the Consolidated Action. In connection with the settlement, the parties agreed that LipoScience would make certain additional disclosures to its stockholders. Subject to the completion of certain confirmatory discovery by counsel, entry by the parties into a stipulation of settlement and customary conditions, including court approval, the settlement will resolve all of the claims that were or could have been brought, including all claims relating to the merger.
	On November 19, 2014, the Company entered into a definitive merger agreement to acquire Covance for approximately $6,200.0 in cash and Company common stock. The transaction closed on February 19, 2015. Prior to the closing of the transaction, purported stockholders of Covance filed two putative class action lawsuits. One of the lawsuits, captioned Berk v. Covance Inc., et al., C.A. No. 10440-VCL, was filed in the Delaware Court of Chancery on December 9, 2014. The other lawsuit, captioned Ojeda v. Herring et al., No. MER-C-92-14, was filed in the Superior Court of New Jersey, Chancery Division, Mercer County, New Jersey, on November 12, 2014. Both suits named as defendants Covance, members of the Covance board of directors, the Company and Neon Merger Sub, Inc., a wholly owned subsidiary of the Company that was merged out of existence in connection with the Acquisition. The lawsuits alleged breach of fiduciary duty and/or other violations of state law arising out of the proposed acquisition. Each suit sought, among other things, injunctive relief enjoining the merger. On January 21, 2015, the case in New Jersey was voluntarily dismissed without prejudice by the Plaintiff. On February 9, 2015, the Plaintiffs in the Delaware case entered into a memorandum of understanding with the Defendants regarding a settlement. In connection with the settlement, the parties agreed that Covance would make additional disclosures to its stockholders. Subject to the entry by the parties into a stipulation of settlement and customary conditions, including court approval, the settlement will resolve all the claims that were or could have been brought, including all claims relating to the merger.
	In December 2014, the Company received a Civil Investigative Demand issued pursuant to the federal False Claims Act from the U.S. Attorney’s Office for South Carolina, which requests information regarding remuneration and services provided by the Company to physicians who also received draw and processing/handling fees from competitor laboratories Health Diagnostic Laboratory, Inc. and Singulex, Inc. The Company is cooperating with the request.
	In March 2015, the Company received a subpoena from the Attorney General of the State of New York, which requests information regarding the Company’s relationship with Direct Laboratories LLC. The Company is cooperating with the request.
	The Company holds an investment in a joint venture partnership located in Alberta, Canada. The Canadian partnership has a license to conduct diagnostic testing services in the province of Alberta. Substantially all of its revenue is received as reimbursement from the Alberta government's health care programs. In December 2013, Alberta Health Services (“AHS”), the Alberta government's health care program, issued a request for proposals for laboratory services that includes the scope of services performed by the Canadian partnership. In October 2014, AHS informed the Canadian partnership that it had not been selected as the preferred proponent. In November 2014, the Canadian partnership submitted a vendor bid appeal upon the belief that there were significant flaws and failures in the conduct of the request for proposal process, which drove to a biased conclusion. AHS established a Vendor Bid Appeal Panel to hear the appeal, and the hearing was conducted February 23-25, 2015. The decision remains pending before the Vendor Bid Appeal Panel. The Vendor Bid Appeal Panel is not required to respond by a particular date, but the Canadian partnership anticipates a decision on the bid appeal before the end of May 2015. If the appeal is unsuccessful, the Canadian partnership could then pursue a lawsuit to have the case heard in court. The Company believes that the Canadian partnership has a strong fact pattern and legal grounds to be ultimately successful in its challenge to the AHS decision, and it is the Company’s belief and best estimate, based on the facts and legal grounds presented to date, that the Canadian partnership should be successful in its challenge to the validity of the RFP process. The Canadian partnership’s existing contract with AHS remains in place through March 2016. If the AHS contract award remains with the preferred proponent, then the Canadian partnership's revenues, and accordingly the Company’s revenues, would decrease substantially and the carrying value of the Company's investment could potentially be impaired.
	Under the Company's present insurance programs, coverage is obtained for catastrophic exposure as well as those risks required to be insured by law or contract. The Company is responsible for the uninsured portion of losses related primarily to general, professional and vehicle liability, certain medical costs and workers' compensation. The self-insured retentions are on a per occurrence basis without any aggregate annual limit. Provisions for losses expected under these programs are recorded based upon the Company's estimates of the aggregated liability of claims incurred. As of March 31, 2015, the Company had provided letters of credit aggregating approximately $42.5, primarily in connection with certain insurance programs. The Company's availability under its Revolving Credit Facility is reduced by the amount of these letters of credit.

PENSION_AND_POSTRETIREMENT_PLA

PENSION AND POSTRETIREMENT PLANS	3 Months Ended
	Mar. 31, 2015
Postemployment Benefits [Abstract]
Pension And Postretirement Plans	PENSION AND POSTRETIREMENT PLANS
	The Company’s defined contribution retirement plan (the “401K Plan”) covers substantially all pre-Acquisition employees. All employees eligible for the 401K Plan receive a minimum 3% non-elective contribution concurrent with each payroll period. The 401K Plan also permits discretionary contributions by the Company of up to 1% and up to 3% of pay for eligible employees based on years of service with the Company. The cost of this plan was $12.9 and $13.4 for the three months ended March 31, 2015 and 2014, respectively. As a result of the Acquisition, the Company also incurred expense of $4.7 for the Covance 401K Plan during the three months ended March 31, 2015.
	The Company also maintains a frozen defined benefit retirement plan (the “Company Plan”), that as of December 31, 2009, covered substantially all employees. The benefits to be paid under the Company Plan are based on years of credited service through December 31, 2009 and ongoing interest credits. Effective January 1, 2010, the Company Plan was closed to new participants. The Company’s policy is to fund the Company Plan with at least the minimum amount required by applicable regulations.
	The Company maintains a second unfunded, non-contributory, non-qualified defined benefit retirement plan (the “PEP”), that as of December 31, 2009, covered substantially all of its senior management group. The PEP supplements the Company Plan and was closed to new participants effective January 1, 2010.
	The effect on operations for the Company Plan and the PEP is summarized as follows:
		Three Months Ended March 31,
		2015			2014
	Service cost for administrative expenses	$	1		$	0.9
	Interest cost on benefit obligation	3.8			3.9
	Expected return on plan assets	(4.6		)	(4.4		)
	Net amortization and deferral	2.7			1.8
	Defined benefit plan costs	$	2.9		$	2.2
	During the three months ended March 31, 2015, the Company contributed $2.2 to the Company Plan.
	The Company has assumed obligations under a subsidiary’s post-retirement medical plan. Coverage under this plan is restricted to a limited number of existing employees of the subsidiary. This plan is unfunded and the Company’s policy is to fund benefits as claims are incurred. The effect on operations of the post-retirement medical plan is shown in the following table:
		Three Months Ended March 31,
		2015			2014
	Service cost for benefits earned	$	0.1		$	0.1
	Interest cost on benefit obligation	0.3			0.4
	Net amortization and deferral	(2.4		)	(1.9		)
	Post-retirement medical plan benefits	$	(2.0	)	$	(1.4	)
	In addition to the PEP, the as a result of the Acquisition, the Company also has a a frozen non-qualified Supplemental Executive Retirement Plan (“SERP”). The SERP, which is not funded, is intended to provide retirement benefits for certain executive officers of the Company. Benefit amounts are based upon years of service and compensation of the participating employees. The pension benefit obligation as of the Acquisition date was $32.8. The components of the net periodic pension cost for the three months ended March 31, 2015 are as follows:
	Service cost	$	0.4
	Interest cost	0.9
	Net amortization and deferral	—
	Net periodic pension cost	$	1.3
	Also as a result of the Acquisition, the Company sponsors a post-employment retiree health and welfare plan for the benefit of eligible employees at certain U.S. subsidiaries who retire after satisfying service and age requirements. This plan is funded on a pay-as-you-go basis and the cost of providing these benefit is shared with the retirees. The net periodic post-retirement benefit cost for the three months ended March 31, 2015 was $0.2 and the pension benefit obligation as of the Acquisition date was $6.3.
	As a result of the Acquisition, the Company sponsors two defined benefit pension plans for the benefit of its employees at two United Kingdom subsidiaries and one defined benefit pension plan for the benefit of its employees at a German subsidiary, all of which are legacy plans of previously acquired companies. Benefit amounts for all three plans are based upon years of service and compensation. The German plan is unfunded while the United Kingdom pension plans are funded. The Company’s funding policy has been to contribute annually a fixed percentage of the eligible employee’s salary at least equal to the local statutory funding requirements.
		United Kingdom Plans				German Plan
		Three Months Ended March 31, 2015				Three Months Ended March 31, 2015
	Service cost for administrative expenses	$	0.3			$	0.1
	Interest cost on benefit obligation	0.9				—
	Expected return on plan assets	(1.3		)		—
	Net amortization and deferral	0.2				0.1
	Defined benefit plan costs	$	0.1			$	0.2
	Assumptions used to determine defined benefit plan cost
	Discount rate	3.6		%		2.2		%
	Expected return on assets	5.4		%		N/A
	Salary increases	3.5		%		2		%

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS
	The Company’s population of financial assets and liabilities subject to fair value measurements as of March 31, 2015 and December 31, 2014 is as follows:
				Fair Value Measurements as of
		Fair Value		March 31, 2015
		as of		Using Fair Value Hierarchy
		March 31, 2015		Level 1		Level 2		Level 3
	Noncontrolling interest put	$	16.2	$	—	$	16.2	$	—
	Interest rate swap	34		—		34		—
	Cash surrender value of life insurance policies	44.7		—		44.7		—
	Deferred compensation liability	43.1		—		43.1		—
				Fair Value Measurements as of
		Fair Value		December 31, 2014
		as of		Using Fair Value Hierarchy
		December 31, 2014		Level 1		Level 2		Level 3
	Noncontrolling interest put	$	17.7	$	—	$	17.7	$	—
	Interest rate swap	18.5		—		18.5		—
	Cash surrender value of life insurance policies	41.9		—		41.9		—
	Deferred compensation liability	43.4		—		43.4		—
	The Company has a noncontrolling interest put related to its Ontario subsidiary that has been classified as mezzanine equity in the Company’s condensed consolidated balance sheet. The noncontrolling interest put is valued at its contractually determined value, which approximates fair value.
	The Company offers certain employees the opportunity to participate in a deferred compensation plan (“DCP”). A participant's deferrals are allocated by the participant to one or more of 16 measurement funds, which are indexed to externally managed funds. From time to time, to offset the cost of the growth in the participant's investment accounts, the Company purchases life insurance policies, with the Company named as beneficiary of the policies. Changes in the cash surrender value of these policies are based upon earnings and changes in the value of the underlying investments, which are typically invested in a manner similar to the participants' allocations. Changes in the fair value of the DCP obligation are derived using quoted prices in active markets based on the market price per unit multiplied by the number of units. The cash surrender value and the DCP obligations are classified within Level 2 because their inputs are derived principally from observable market data by correlation to the hypothetical investments.
	The carrying amounts of cash and cash equivalents, accounts receivable, income taxes receivable, and accounts payable are considered to be representative of their respective fair values due to their short-term nature. The fair market value of the zero-coupon subordinated notes, based on market pricing, was approximately $181.1 and $155.6 as of March 31, 2015 and December 31, 2014, respectively. The fair market value of all of the senior notes, based on market pricing, was approximately $6,586.8 and $2,949.8 as of March 31, 2015 and December 31, 2014, respectively. The Company's note and debt instruments are classified as Level 2 instruments, as the fair market values of these instruments are determined using other observable inputs.

DERIVATIVE_INSTRUMENTS_AND_HED

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments And Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES
	The Company addresses its exposure to market risks, principally the market risk associated with changes in interest rates, through a controlled program of risk management that includes, from time to time, the use of derivative financial instruments such as interest rate swap agreements (see Interest Rate Swap section below). Although the Company’s zero-coupon subordinated notes contain features that are considered to be embedded derivative instruments (see Embedded Derivatives Related to the Zero-Coupon Subordinated Notes section below), the Company does not hold or issue derivative financial instruments for trading purposes. The Company does not believe that its exposure to market risk is material to the Company’s financial position or results of operations.
	Interest Rate Swap
	During the third quarter of 2013, the Company entered into two fixed-to-variable interest rate swap agreements for its 4.625% senior notes due 2020 with an aggregate notional amount of $600.0 and variable interest rates based on one-month LIBOR plus 2.298% to hedge against changes in the fair value of a portion of the Company's long term debt.  These derivative financial instruments are accounted for as fair value hedges of the senior notes due 2020.  These interest rate swaps are included in other long term assets and added to the value of the senior notes, with an aggregate fair value of $34.0 and $18.5 at March 31, 2015 and December 31, 2014, respectively. As the specific terms and notional amounts of the derivative financial instruments match those of the fixed-rate debt being hedged, the derivative instruments are assumed to be perfectly effective hedges and accordingly, there is no impact to the Company's consolidated statements of operations.
	Embedded Derivatives Related to the Zero-Coupon Subordinated Notes
	The Company’s zero-coupon subordinated notes contain the following two features that are considered to be embedded derivative instruments under authoritative guidance in connection with accounting for derivative instruments and hedging activities:
	1)	The Company will pay contingent cash interest on the zero-coupon subordinated notes after September 11, 2006, if the average market price of the notes equals 120% or more of the sum of the issue price, accrued original issue discount and contingent additional principal, if any, for a specified measurement period.
	2)	Holders may surrender zero-coupon subordinated notes for conversion during any period in which the rating assigned to the zero-coupon subordinated notes by Standard & Poor’s Ratings Services is BB- or lower.
	The Company believes these embedded derivatives had no fair value at March 31, 2015 and December 31, 2014. These embedded derivatives also had no impact on the condensed consolidated statements of operations for the three months ended March 31, 2015 and 2014, respectively.

SUPPLEMENTAL_CASH_FLOW_INFORMA

SUPPLEMENTAL CASH FLOW INFORMATION	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	SUPPLEMENTAL CASH FLOW INFORMATION
		Three Months Ended March 31,
		2015			2014
	Supplemental schedule of cash flow information:
	Cash paid during period for:
	Interest	$	14.9		$	18.8
	Income taxes, net of refunds	23.1			8.6
	Disclosure of non-cash financing and investing activities:
	Surrender of restricted stock awards and performance awards	$	7.8		$	4.6
	Non-cash stock consideration for the Acquisition	1,762.50			—
	Conversion of zero-coupon convertible debt	—			2.8
	Assets acquired under capital leases	16.7			3.1
	Increase (decrease) accrued property, plant and equipment	(1.4		)	4.7

BUSINESS_SEGMENT_INFORMATION_B

BUSINESS SEGMENT INFORMATION Business Segment information (Notes)	3 Months Ended
	Mar. 31, 2015
Segment Reporting Information [Line Items]
Segment Reporting Disclosure [Text Block]	BUSINESS SEGMENT INFORMATION
	The following table is a summary of segment information for the three months ended March 31, 2015 and 2014. The “management approach” has been used to present the following segment information. This approach is based upon the way the management of the Company organizes segments within an enterprise for making operating decisions and assessing performance. Financial information is reported on the basis that it is used internally by the chief operating decision maker (“CODM”) for evaluating segment performance and deciding how to allocate resources to segments. The Company’s chief executive officer has been identified as the CODM.
	Prior to the first quarter of 2015, the CODM managed the operating results of the Company as two segments: clinical laboratory diagnostics and other. In connection with the Acquisition, the Company changed its operating segments to align with how the CODM evaluates financial information used to allocate resources and assess performance of the Company post Acquisition. As a result, the segment information presented in these financial statements has been conformed to present segments on this revised basis for all prior periods. Under the new organizational structure, the CODM manages the Company under two segments: LCD and CDD. LCD includes all of the legacy LabCorp business and the nutritional chemistry and food safety business, which were previously part of Covance but excludes LabCorp's legacy clinical trials testing business, which is now part of CDD. CDD includes all of Covance's legacy business and LabCorp's legacy clinical trials testing business, but excludes the nutritional chemistry and food safety business, which are now part of LCD.
	Segment asset information is not presented because it is not used by the CODM at the segment level. Operating earnings (loss) of each segment represents net revenues less directly identifiable expenses to arrive at operating income for the segment. General management and administrative corporate expenses are included in general corporate expenses below. The accounting policies of the segments are the same as those as set forth in Note 1 to the Consolidated Financial Statements contained in the Company's Annual Report on Form 10-K for the year ended December 31, 2014 and Note 1 (Basis of Financial Statement Presentation) above to the interim condensed consolidated financial statements.
	The table below represents information about the Company’s reporting segments for the three months ended March 31, 2015 and 2014:
		Three Months Ended
		March 31,
		2015			2014
	Total revenues:
	LCD - net revenue	$	1,472.00		$	1,392.90
	CDD - net revenue	300.3			37.8
	CDD - reimbursable out-of-pocket expenses	20.9			—
	Total revenues	1,793.20			1,430.70
	Operating earnings (loss):
	LCD	222.8			232.3
	CDD	(54.4		)	4.5
	Unallocated corporate expenses	(38.2		)	(33.5		)
	Total operating income	130.2			203.3
	Other income (expense), net	(99.9		)	(15.6		)
	Earnings before income taxes	30.3			187.7
	Provision for income taxes	29.3			74.2
	Net earnings	1			113.5
	Less income attributable to noncontrolling interests	(0.3		)	(0.4		)
	Net income attributable to Laboratory Corporation of America Holdings	$	0.7		$	113.1

EARNINGS_PER_SHARE_Tables

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Reconciliation of Basic earnings per Share to Diluted Earnings per Share	The following represents a reconciliation of basic earnings per share to diluted earnings per share:
		Three Months Ended March 31,
		2015						2014
		Earnings			Shares	Per		Earnings		Shares	Per
						Share					Share
						Amount					Amount
	Basic earnings per share:
	Net earnings	$	0.7		91.9	$	0.01	$	113.1	85.2	$	1.33
	Dilutive effect of employee stock options and awards	—			1.2			—		0.9
	Effect of convertible debt	—			0.7			—		0.5
	Diluted earnings per share:
	Net earnings including impact of dilutive adjustments	$	0.7		93.8	$	0.01	$	113.1	86.6	$	1.31
Potential common shares not included in computation of diluted earnings per share	The following table summarizes the potential common shares not included in the computation of diluted earnings per share because their impact would have been antidilutive:
		Three Months Ended March 31,
		2015		2014
	Stock options	—		—

RESTRUCTURING_AND_OTHER_SPECIA1

RESTRUCTURING AND OTHER SPECIAL CHARGES Restructuring and Other Special Charges Detail (Tables)	3 Months Ended
	Mar. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Costs [Table Text Block]	RESTRUCTURING AND OTHER SPECIAL CHARGES
	During the first three months of 2015, the Company recorded net restructuring and other special charges of $19.3. The charges were comprised of $3.2 related to severance and other personnel costs along with $16.1 in costs associated with facility closures and impairment of certain information technology assets.
	In addition, during the first three months of 2015, the Company recorded $6.0 in consulting expenses (recorded in selling, general and administrative expenses) relating to fees incurred as part of its business process improvement initiative (“Project LaunchPad”). The Company also recorded $166.0 of deal costs related to the Acquisition, of which $80.6 is included in selling, general and administrative expenses, $32.8 is included in cost of revenue, and $52.6 is included in interest expense.
	During the first three months of 2014, the Company recorded net restructuring and other special charges of $7.6. The charges were comprised of $2.8 related to severance and other personnel costs along with $4.9 in costs associated with facility closures and general integration initiatives. These charges were offset by the reversal of previously established reserves of $0.1 in unused severance.
	The following represents the Company’s restructuring reserve activities for the period indicated:
		Severance			Lease			Total
		and Other			and Other
		Employee			Facility
		Costs			Costs
	Balance as of December 31, 2014	$	0.4		$	21.7		$	22.1
	Restructuring charges	3.2			16.1			19.3
	Reduction of prior restructuring accruals	—			—			—
	Cash payments and other adjustments	(2.9		)	(17.0		)	(19.9		)
	Balance as of March 31, 2015	$	0.7		$	20.8		$	21.5
	Current							$	7.5
	Non-current							14
								$	21.5
		Severance			Lease			Total
		and Other			and Other
		Employee			Facility
		Costs			Costs
	Balance as of December 31, 2014	$	0.4		$	21.7		$	22.1
	Restructuring charges	3.2			16.1			19.3
	Reduction of prior restructuring accruals	—			—			—
	Cash payments and other adjustments	(2.9		)	(17.0		)	(19.9		)
	Balance as of March 31, 2015	$	0.7		$	20.8		$	21.5
	Current							$	7.5
	Non-current							14
								$	21.5

GOODWILL_AND_INTANGIBLE_ASSETS1

GOODWILL AND INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill for the three month period ended March 31, 2015 and for the year ended December 31, 2014 are as follows:
		LCD						CDD				Total
		March 31,			December 31, 2014			March 31,		December 31, 2014		March 31,			December 31, 2014
		2015						2015				2015
	Balance as of January 1	$	2,988.90		$	2,912.30		$	110.5	$	110.5	$	3,099.40		$	3,022.80
	Goodwill acquired during the period	11.5			81.8			3,176.10		—		3,187.60			81.8
	Adjustments to goodwill	(4.8		)	(5.2		)	—		—		(4.8		)	(5.2		)
	Balance at end of period	$	2,995.60		$	2,988.90		$	3,286.60	$	110.5	$	6,282.20		$	3,099.40
Components of identifiable intangible assets	The components of identifiable intangible assets are as follows:
		March 31, 2015								December 31, 2014
		Gross			Accumulated			Net		Gross		Accumulated			Net
		Carrying			Amortization					Carrying		Amortization
		Amount								Amount
	Customer relationships	$	3,281.00		$	(630.1	)	$	2,650.90	$	1,361.60	$	(606.8	)	$	754.8
	Patents, licenses and technology	122.2			(98.4		)	23.8		125.9		(95.9		)	30
	Non-compete agreements	46.1			(33.2		)	12.9		45.6		(31.7		)	13.9
	Trade names	424.3			(95.8		)	328.5		133.3		(91.6		)	41.7
	Land use right	4.9			(0.2		)	4.7		—		—			—
	Canadian licenses	582.5			—			582.5		635.4		—			635.4
		$	4,461.00		$	(857.7	)	$	3,603.30	$	2,301.80	$	(826.0	)	$	1,475.80

DEBT_Tables

DEBT (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Short-term borrowings and current portion of long-term debt	Short-term borrowings and the current portion of long-term debt at March 31, 2015 and December 31, 2014 consisted of the following:
		March 31,		December 31, 2014
		2015
	Zero-coupon convertible subordinated notes	$	94.4	$	93.9
	5.625% senior notes due 2015	250		250
	Current portion of capital leases	4.2		3.2
	Total short-term borrowings and current portion of long-term debt	$	348.6	$	347.1
Long-term debt	Long-term debt at March 31, 2015 and December 31, 2014 consisted of the following:
		March 31,		December 31, 2014
		2015
	3.125% senior notes due 2016	$	325	$	325
	2.20% senior notes due 2017	500		500
	2.50% senior notes due 2018	400		400
	4.625% senior notes due 2020	634		618.5
	2.625% senior notes due 2020	500		—
	3.75% senior notes due 2022	500		500
	3.20% senior notes due 2022	500		—
	4.00% senior notes due 2023	300		300
	3.60% senior notes due 2025	1,000.00		—
	4.70% senior notes due 2045	900		—
	Revolving credit facility	60		—
	Term loan	925		—
	Capital leases	53.7		39.2
	Total long-term debt	$	6,597.70	$	2,682.70

PREFERRED_STOCK_AND_COMMON_SHA1

PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The components of accumulated other comprehensive earnings are as follows:
		Foreign				Net			Unrealized Gains and Losses on Available for Sale Securities			Accumulated
		Currency				Benefit						Other
		Translation				Plan						Comprehensive
		Adjustments				Adjustments						Earnings
	Balance at December 31, 2014	$	68			$	(78.6	)	$	0.1		$	(10.5	)
	Other comprehensive earnings before reclassifications	(168.5		)		1.2			(0.1		)	(167.4		)
	Amounts reclassified from accumulated other comprehensive earnings to the Condensed Consolidated Statement of Operations (a)	—				(0.3		)	—			(0.3		)
	Tax effect of adjustments	47.4				(0.3		)	—			47.1
	Balance at March 31, 2015	$	(53.1	)		$	(78.0	)	$	—		$	(131.1	)
Changes in common shares issued and held in treasury	The changes in common shares issued and held in treasury are summarized below:
		Issued			Held in			Outstanding
					Treasury
	Common shares at December 31, 2014	107.1			(22.5	)		84.6
	Common stock issued in conjunction with the Acquisition	15.3			—			15.3
	Common stock issued under employee stock plans	0.6			—			0.6
	Common shares at March 31, 2015	123			(22.5	)		100.5

PENSION_AND_POSTRETIREMENT_PLA1

PENSION AND POSTRETIREMENT PLANS (Tables)	3 Months Ended
	Mar. 31, 2015
Postemployment Benefits [Abstract]
Schedule of Pensions and Postretirement Plans	The effect on operations for the Company Plan and the PEP is summarized as follows:
		Three Months Ended March 31,
		2015			2014
	Service cost for administrative expenses	$	1		$	0.9
	Interest cost on benefit obligation	3.8			3.9
	Expected return on plan assets	(4.6		)	(4.4		)
	Net amortization and deferral	2.7			1.8
	Defined benefit plan costs	$	2.9		$	2.2
	The effect on operations of the post-retirement medical plan is shown in the following table:
		Three Months Ended March 31,
		2015			2014
	Service cost for benefits earned	$	0.1		$	0.1
	Interest cost on benefit obligation	0.3			0.4
	Net amortization and deferral	(2.4		)	(1.9		)
	Post-retirement medical plan benefits	$	(2.0	)	$	(1.4	)
	In addition to the PEP, the as a result of the Acquisition, the Company also has a a frozen non-qualified Supplemental Executive Retirement Plan (“SERP”). The SERP, which is not funded, is intended to provide retirement benefits for certain executive officers of the Company. Benefit amounts are based upon years of service and compensation of the participating employees. The pension benefit obligation as of the Acquisition date was $32.8. The components of the net periodic pension cost for the three months ended March 31, 2015 are as follows:
	Service cost	$	0.4
	Interest cost	0.9
	Net amortization and deferral	—
	Net periodic pension cost	$	1.3
	Also as a result of the Acquisition, the Company sponsors a post-employment retiree health and welfare plan for the benefit of eligible employees at certain U.S. subsidiaries who retire after satisfying service and age requirements. This plan is funded on a pay-as-you-go basis and the cost of providing these benefit is shared with the retirees. The net periodic post-retirement benefit cost for the three months ended March 31, 2015 was $0.2 and the pension benefit obligation as of the Acquisition date was $6.3.
	As a result of the Acquisition, the Company sponsors two defined benefit pension plans for the benefit of its employees at two United Kingdom subsidiaries and one defined benefit pension plan for the benefit of its employees at a German subsidiary, all of which are legacy plans of previously acquired companies. Benefit amounts for all three plans are based upon years of service and compensation. The German plan is unfunded while the United Kingdom pension plans are funded. The Company’s funding policy has been to contribute annually a fixed percentage of the eligible employee’s salary at least equal to the local statutory funding requirements.
		United Kingdom Plans				German Plan
		Three Months Ended March 31, 2015				Three Months Ended March 31, 2015
	Service cost for administrative expenses	$	0.3			$	0.1
	Interest cost on benefit obligation	0.9				—
	Expected return on plan assets	(1.3		)		—
	Net amortization and deferral	0.2				0.1
	Defined benefit plan costs	$	0.1			$	0.2
	Assumptions used to determine defined benefit plan cost
	Discount rate	3.6		%		2.2		%
	Expected return on assets	5.4		%		N/A
	Salary increases	3.5		%		2		%

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Company's population of financial assets and liabilities subject to fair value measurements	The Company’s population of financial assets and liabilities subject to fair value measurements as of March 31, 2015 and December 31, 2014 is as follows:
				Fair Value Measurements as of
		Fair Value		March 31, 2015
		as of		Using Fair Value Hierarchy
		March 31, 2015		Level 1		Level 2		Level 3
	Noncontrolling interest put	$	16.2	$	—	$	16.2	$	—
	Interest rate swap	34		—		34		—
	Cash surrender value of life insurance policies	44.7		—		44.7		—
	Deferred compensation liability	43.1		—		43.1		—
				Fair Value Measurements as of
		Fair Value		December 31, 2014
		as of		Using Fair Value Hierarchy
		December 31, 2014		Level 1		Level 2		Level 3
	Noncontrolling interest put	$	17.7	$	—	$	17.7	$	—
	Interest rate swap	18.5		—		18.5		—
	Cash surrender value of life insurance policies	41.9		—		41.9		—
	Deferred compensation liability	43.4		—		43.4		—

SUPPLEMENTAL_CASH_FLOW_INFORMA1

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information
		Three Months Ended March 31,
		2015			2014
	Supplemental schedule of cash flow information:
	Cash paid during period for:
	Interest	$	14.9		$	18.8
	Income taxes, net of refunds	23.1			8.6
	Disclosure of non-cash financing and investing activities:
	Surrender of restricted stock awards and performance awards	$	7.8		$	4.6
	Non-cash stock consideration for the Acquisition	1,762.50			—
	Conversion of zero-coupon convertible debt	—			2.8
	Assets acquired under capital leases	16.7			3.1
	Increase (decrease) accrued property, plant and equipment	(1.4		)	4.7

BUSINESS_SEGMENT_INFORMATION_T

BUSINESS SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]
		Three Months Ended
		March 31,
		2015			2014
	Total revenues:
	LCD - net revenue	$	1,472.00		$	1,392.90
	CDD - net revenue	300.3			37.8
	CDD - reimbursable out-of-pocket expenses	20.9			—
	Total revenues	1,793.20			1,430.70
	Operating earnings (loss):
	LCD	222.8			232.3
	CDD	(54.4		)	4.5
	Unallocated corporate expenses	(38.2		)	(33.5		)
	Total operating income	130.2			203.3
	Other income (expense), net	(99.9		)	(15.6		)
	Earnings before income taxes	30.3			187.7
	Provision for income taxes	29.3			74.2
	Net earnings	1			113.5
	Less income attributable to noncontrolling interests	(0.3		)	(0.4		)
	Net income attributable to Laboratory Corporation of America Holdings	$	0.7		$	113.1

BASIS_OF_FINANCIAL_STATEMENT_P1

BASIS OF FINANCIAL STATEMENT PRESENTATION (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables, Current	$72.40
Ownership percentage below which investments are generally accounted for on the cost method (in thousandths)	20.00%

EARNINGS_PER_SHARE_Reconciliat

EARNINGS PER SHARE (Reconciliation of Basic Earnings Per Share to Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income [Abstract]
Net earnings, basic	$0.70	$113.10
Net earnings including impact of dilutive adjustments	$0.70	$113.10
Shares [Abstract]
Net earnings, basic (in shares)	91.9	85.2
Dilutive effect of employee stock options and awards, (in shares)	1.2	0.9
Effect of convertible debt, net of tax, (in shares)	0.7	0.5
Net earnings including impact of dilutive adjustments, (in shares)	93.8	86.6
Per Share Amount [Abstract]
Basic earnings per common share (in dollars per share)	$0.01	$1.33
Diluted earnings per common share (in dollars per share)	$0.01	$1.31

EARNINGS_PER_SHARE_Potential_c

EARNINGS PER SHARE (Potential common shares not included in computation of diluted earnings per share) (Details)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Stock options (in shares)	0	0

RESTRUCTURING_AND_OTHER_SPECIA2

RESTRUCTURING AND OTHER SPECIAL CHARGES (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$21.50		$22.10
Restructuring Charges	19.3
Restructuring Reserve Settled With Cash And Other Adjustment	-19.9
Net restructuring charges	19.3	7.6
Reduction in prior employee severance benefits related restructuring accruals		0.1
Other Special Charges	6
Restructuring charges related to severance and other employee costs	3.2	2.8
Restructuring charges related to contractual obligations associated with leased facilities and other facility related costs	16.1	4.9
Reduction in total prior restructuring accruals	0
Restructuring Reserve, Current	7.5
Restructuring Reserve, Noncurrent	14
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0.7		0.4
Restructuring Charges	3.2
Restructuring Reserve Settled With Cash And Other Adjustment	-2.9
Reduction in total prior restructuring accruals	0
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	20.8		21.7
Restructuring Charges	16.1
Restructuring Reserve Settled With Cash And Other Adjustment	-17
Reduction in total prior restructuring accruals	$0

RESTRUCTURING_RESERVES_Details

RESTRUCTURING RESERVES (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$22.10
Restructuring charges	19.3
Reduction of prior restructuring accruals	0
Cash payments and other adjustments	-19.9
Balance, end of period	21.5
Current	7.5
Non-current	14
Total Restructuring Reserve	21.5
Severance and Other Employee Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	0.4
Restructuring charges	3.2
Reduction of prior restructuring accruals	0
Cash payments and other adjustments	-2.9
Balance, end of period	0.7
Total Restructuring Reserve	0.7
Lease and Other Facility Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	21.7
Restructuring charges	16.1
Reduction of prior restructuring accruals	0
Cash payments and other adjustments	-17
Balance, end of period	20.8
Total Restructuring Reserve	$20.80

GOODWILL_AND_INTANGIBLE_ASSETS2

GOODWILL AND INTANGIBLE ASSETS (Changes in Carrying Amount of Goodwill) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Goodwill [Line Items]
Balance as of January 1	$3,099.40	$3,022.80
Goodwill acquired during the period	3,187.60	81.8
Adjustments to goodwill	-4.8	-5.2
Balance at end of period	6,282.20
LabCorp Diagnostics [Member]
Goodwill [Line Items]
Balance as of January 1	2,988.90
Goodwill acquired during the period	11.5
Adjustments to goodwill	-4.8
Balance at end of period	2,995.60
Clinical diagnostics laboratory [Member]
Goodwill [Line Items]
Balance as of January 1		2,912.30	2,988.90
Goodwill acquired during the period		81.8
Adjustments to goodwill		-5.2
Balance at end of period			2,988.90
Covance Drug Development [Member]
Goodwill [Line Items]
Balance as of January 1	110.5	110.5
Goodwill acquired during the period	3,176.10	0
Adjustments to goodwill	0	0
Balance at end of period	3,286.60
Other Segments [Member]
Goodwill [Line Items]
Balance as of January 1			110.5
Balance at end of period			$110.50

GOODWILL_AND_INTANGIBLE_ASSETS3

GOODWILL AND INTANGIBLE ASSETS (Components of identifiable intangible assets) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$4,461	$2,301.80
Accumulated Amortization	-857.7	-826
Intangible Assets, Net (Excluding Goodwill)	3,603.30	1,475.80
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,281	1,361.60
Accumulated Amortization	-630.1	-606.8
Intangible Assets, Net (Excluding Goodwill)	2,650.90	754.8
Patents, Licenses And Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	122.2	125.9
Accumulated Amortization	-98.4	-95.9
Intangible Assets, Net (Excluding Goodwill)	23.8	30
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	46.1	45.6
Accumulated Amortization	-33.2	-31.7
Intangible Assets, Net (Excluding Goodwill)	12.9	13.9
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	424.3	133.3
Accumulated Amortization	-95.8	-91.6
Intangible Assets, Net (Excluding Goodwill)	328.5	41.7
Use Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4.9	0
Accumulated Amortization	-0.2	0
Intangible Assets, Net (Excluding Goodwill)	4.7	0
Canadian licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	582.5	635.4
Accumulated Amortization	0	0
Intangible Assets, Net (Excluding Goodwill)	$582.50	$635.40

GOODWILL_AND_INTANGIBLE_ASSETS4

GOODWILL AND INTANGIBLE ASSETS (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Jan. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 19, 2015
Finite-Lived Intangible Assets [Line Items]
Senior Notes, Noncurrent			$2,900
Goodwill	6,282.20			3,099.40	3,022.80
Amortization of intangible assets	31.4	21
Finite-Lived Intangible Assets, Future Amortization Expense
Estimated amortization expense, 2012		132.8
Estimated amortization expense, 2013		171.4
Estimated amortization expense, 2014		164.2
Estimated amortization expense, 2015		152.2
Estimated amortization expense, 2016		145.2
Estimated amortization expense, Thereafter		2,239.80
LabCorp Diagnostics [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	2,995.60			2,988.90
Other Segments [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill				110.5
Covance [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill						3,176.10
Senior notes due 2045 [Member]
Finite-Lived Intangible Assets [Line Items]
Senior Notes, Noncurrent			$900

DEBT_Shortterm_borrowings_and_

DEBT (Short-term borrowings and current portion of long-term debt) (Table) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Mar. 31, 2015	Jan. 30, 2015	Nov. 19, 2010	Dec. 19, 2014	Nov. 02, 2014
Short-term Debt [Line Items]
Senior Notes, Noncurrent			$2,900
Capital Lease Obligations, Current	3.2	4.2
Total short-term borrowings and current portion of long-term debt	347.1	348.6
Zero-coupon convertible subordinated notes [Member]
Short-term Debt [Line Items]
Total short-term borrowings and current portion of long-term debt	93.9	94.4
Senior notes due 2020 [Member]
Short-term Debt [Line Items]
Senior Notes, Noncurrent	0	500	500
Debt Instrument, Interest Rate, Stated Percentage		4.63%	2.63%	4.63%
Senior notes due 2022 [Member]
Short-term Debt [Line Items]
Senior Notes, Noncurrent	0	500	500
Debt Instrument, Interest Rate, Stated Percentage		3.75%	3.20%
Senior notes due 2016 [Member]
Short-term Debt [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.63%
Long-term Debt, Excluding Current Maturities	250	250
Senior notes due 2025 [Member]
Short-term Debt [Line Items]
Senior Notes, Noncurrent			1,000
Debt Instrument, Interest Rate, Stated Percentage			3.60%
Senior notes due 2045 [Member]
Short-term Debt [Line Items]
Senior Notes, Noncurrent			900
Debt Instrument, Interest Rate, Stated Percentage			4.70%
365-Day Debt Bridge Traunche [Member]
Short-term Debt [Line Items]
Bridge Term Credit Facility Agreement, Maximum Borrowing Capacity					2,850	3,850
60-Day Debt Bridge Traunche [Domain]
Short-term Debt [Line Items]
Short-term Debt, Terms	P60D
Bridge Term Credit Facility Agreement, Maximum Borrowing Amount					400	400
365-Day Debt Bridge Traunche [Domain]
Short-term Debt [Line Items]
Short-term Debt, Terms	P364D
Covance [Member]
Short-term Debt [Line Items]
Net Proceeds from Debt			2,870.20
Bridge Term Credit Facility Agreement, Maximum Borrowing Amount					$3,250	$4,250

DEBT_Longterm_debt_Table_Detai

DEBT (Long-term debt) (Table) (Details) (USD $)

3 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Mar. 31, 2015

Dec. 31, 2014

Dec. 31, 2014

Jan. 30, 2015

Dec. 19, 2014

Nov. 19, 2010

Feb. 19, 2015

Nov. 02, 2014

Feb. 18, 2015

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Quarters

Debt Instrument [Line Items]

Debt to EBITDA (Leverage) Ratio

4.2

Total long-term debt

$6,597.70

2,682.70

2,682.70

Line of Credit Facility, Fair Value of Amount Outstanding

60

0

0

Other Long-term Debt

925

0

0

Debt Instrument, Face Amount

600

Senior Notes, Noncurrent

2,900

Capital Lease Obligations

53.7

39.2

39.2

Debt Covenant Requirement for Number of Consecutive Fiscal Quarters

Revolving Credit Facility covenant terms ceiling

0

Line of Credit Facility, Maximum Borrowing Capacity

1,000

Credit Facility Option to Increase

250

Credit Facility, Maximum Swing Line Borrowings

100

Capital lease obligation

4.2

3.2

3.2

Senior notes due 2015 [Member]

Debt Instrument [Line Items]

Stated interest rate percentage

5.63%

Senior notes due 2016 [Member]

Debt Instrument [Line Items]

Total long-term debt

325

325

325

Stated interest rate percentage

3.13%

Senior notes due 2017 [Member]

Debt Instrument [Line Items]

Total long-term debt

500

500

500

Stated interest rate percentage

2.20%

Senior notes due 2018 [Member]

Debt Instrument [Line Items]

Total long-term debt

400

400

400

Senior notes due 2020 [Member]

Debt Instrument [Line Items]

Total long-term debt

634

Debt Instrument, Face Amount

618.5

618.5

Senior Notes, Noncurrent

500

0

0

500

Stated interest rate percentage

4.63%

2.63%

4.63%

Senior notes due 2022 [Member]

Debt Instrument [Line Items]

Total long-term debt

500

500

500

Senior Notes, Noncurrent

500

0

0

500

Stated interest rate percentage

3.75%

3.20%

Senior notes due 2025 [Member]

Debt Instrument [Line Items]

Senior Notes, Noncurrent

1,000

Stated interest rate percentage

3.60%

Senior notes due 2023 [Member]

Debt Instrument [Line Items]

Total long-term debt

300

300

300

Senior notes due 2025 [Member] [Member]

Debt Instrument [Line Items]

Total long-term debt

1,000

0

0

Senior notes due 2045 [Member]

Debt Instrument [Line Items]

Total long-term debt

900

0

0

Senior Notes, Noncurrent

900

Stated interest rate percentage

4.70%

Long-term Debt [Member]

Debt Instrument [Line Items]

Debt Instrument, Interest Rate, Effective Percentage

1.47%

Covance [Member]

Debt Instrument [Line Items]

Bridge Term Credit Facility Agreement, Maximum Borrowing Amount

3,250

4,250

Other Long-term Debt

1,000,000

Net Proceeds from Debt

2,870.20

Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Initiation Date

19-Dec-14

Credit Facility, Maximum Letters of Credit

125

60-Day Debt Bridge Traunche [Domain]

Debt Instrument [Line Items]

Bridge Term Credit Facility Agreement, Maximum Borrowing Amount

400

400

Short-term Debt, Terms

P60D

365-Day Debt Bridge Traunche [Domain]

Debt Instrument [Line Items]

Short-term Debt, Terms

P364D

365-Day Debt Bridge Traunche [Member]

Debt Instrument [Line Items]

Bridge Term Credit Facility Agreement, Maximum Borrowing Capacity

$2,850

$3,850

Maximum [Member] | Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Debt to EBITDA (Leverage) Ratio

3.75

Prime Rate [Member] | Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Interest Rate Description

0.00% to 0.60%

Prime Rate [Member] | Term Loan [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Interest Rate Description

0.125% to 1.00%

London Interbank Offered Rate (LIBOR) [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Commitment Fee Description

0.125% to 0.40%

London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Interest Rate Description

1.00% to 1.60%

London Interbank Offered Rate (LIBOR) [Member] | Term Loan [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Interest Rate Description

1.125% to 2.00%

Scenario, Forecast [Member] | Maximum [Member] | Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Debt to EBITDA (Leverage) Ratio

3.75

4.25

4.75

DEBT_Senior_Notes_Details

DEBT (Senior Notes) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Jan. 30, 2015	Dec. 31, 2014	Dec. 19, 2014	Nov. 19, 2010	Feb. 19, 2015	Nov. 02, 2014
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$1,000
Credit Facility Option to Increase				250
Credit Facility, Maximum Swing Line Borrowings				100
Senior Notes, Noncurrent		2,900
Debt to EBITDA (Leverage) Ratio	4.2
Fair Value Hedges, Net	34		18.5
Debt Instrument, Face Amount	600
Derivative, Basis Spread on Variable Rate	2.30%
Senior notes due 2045 [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent		900
Stated interest rate percentage		4.70%
Senior notes due 2022 [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent	500	500	0
Stated interest rate percentage	3.75%	3.20%
Senior notes due 2017 [Member]
Debt Instrument [Line Items]
Stated interest rate percentage	2.20%
Senior notes due 2020 [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent	500	500	0
Stated interest rate percentage	4.63%	2.63%			4.63%
Debt Instrument, Face Amount			618.5
Covance [Member]
Debt Instrument [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt						250
Make-whole payment	37.4
Bridge Term Credit Facility Agreement, Maximum Borrowing Amount				3,250			4,250
Net Proceeds from Debt		$2,870.20

DEBT_Convertible_Subordinated_

DEBT (Convertible Subordinated Notes) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Zero Coupon Convertible Subordinated Notes [Line Items]
Payments on zero-coupon subordinated notes	$0	($6,900,000)
Zero-coupon convertible subordinated notes [Member]
Zero Coupon Convertible Subordinated Notes [Line Items]
Minimum contingent cash interest rate on zero-coupon subordinated notes (in hundredths)	0.13%
Number of trading days used to establish contingent cash interest rate on zero-coupon subordinated notes (in days)	5
Stock conversion rate for zero-coupon subordinated notes (per thousand)	13.4108
Principal amount of zero-coupon subordinated notes	$1,000
Date of the terms for the zero-coupon subordinated notes and indenture	24-Oct-06

DEBT_Credit_Facilities_Details

DEBT (Credit Facilities) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Mar. 31, 2015	Dec. 19, 2014	Feb. 18, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Line of Credit Facility, Fair Value of Amount Outstanding	0	$60
Revolving Credit Facility, maximum borrowing capacity			1,000
Debt to EBITDA (leverage) ratio		4.2
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving Credit Facility, interest rate at period end		1.28%
Target Ratio to Resume Share Repurchase [Member]
Line of Credit Facility [Line Items]
Debt to EBITDA (leverage) ratio		2.5
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Initiation Date	19-Dec-14
Credit Facility, Maximum Letters of Credit			$125
Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt to EBITDA (leverage) ratio				3.75
Maximum [Member] | Revolving Credit Facility [Member] | Scenario, Forecast [Member]
Line of Credit Facility [Line Items]
Debt to EBITDA (leverage) ratio					3.75	4.25	4.75

PREFERRED_STOCK_AND_COMMON_SHA2

PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Stockholders' Equity Note [Abstract]
Stock Issued During Period, Shares, Acquisitions	15.3
Common stock, shares authorized	265
Common stock, par value per share (in dollars per share)	$0.10
Preferred stock, shares authorized	30
Preferred stock, par value per share (in dollars per share)	$0.10
Preferred stock, shares outstanding	0
Rollforward of common shares issued
Common shares issued, beginning balance (in shares)	107.1
Common stock issued under employee stock plans (in shares)	0.6
Common shares issued, ending balance (in shares)	123
Rollforward of common shares held in treasury
Common shares held in Treasury, beginning balance (in shares)	-22.5
Common shares held in Treasury, ending balance (in shares)	-22.5
Rollforward of common shares outstanding
Common shares outstanding, beginning balance (in shares)	84.6
Common stock issued under employee stock plans (in shares)	0.6
Common shares outstanding, ending balance (in shares)	100.5
Rollforward of Share Repurchase Program
Outstanding common stock repurchase authorization, beginning balance	$789.50
Purchase of common stock	$0	($107.70)

PREFERRED_STOCK_AND_COMMON_SHA3

PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY - Accumulated Other Comprehensive Earnings (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015														Mar. 31, 2014	Dec. 31, 2014
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The components of accumulated other comprehensive earnings are as follows:
		Foreign			Net			Unrealized Gains and Losses on Available for Sale Securities			Accumulated
		Currency			Benefit						Other
		Translation			Plan						Comprehensive
		Adjustments			Adjustments						Earnings
	Balance at December 31, 2014	$	68		$	(78.6	)	$	0.1		$	(10.5	)
	Other comprehensive earnings before reclassifications	(168.5		)	1.2			(0.1		)	(167.4		)
	Amounts reclassified from accumulated other comprehensive earnings to the Condensed Consolidated Statement of Operations (a)	—			(0.3		)	—			(0.3		)
	Tax effect of adjustments	47.4			(0.3		)	—			47.1
	Balance at March 31, 2015	$	(53.1	)	$	(78.0	)	$	—		$	(131.1	)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax	$0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax	1.2
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0.3													[1]
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	-0.1
Other Comprehensive Income (Loss), before Reclassifications, before Tax	-167.4
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	0															0.1
Accumulated Other Comprehensive Earnings [Roll Forward]
Foreign Currency Translation Adjustments, Beginning balance	68
Other comprehensive income before reclassifications	-168.5
Tax effect of adjustments	47.4
Foreign Currency Translation Adjustments, Ending balance	-53.1
Net Benefit Plan Adjustments, Beginning balance	-78.6
Amounts reclassified from accumulated other comprehensive income	-0.3													[1]
Tax effect of adjustments	-0.3
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	0
Net Benefit Plan Adjustments, Ending balance	-78
Accumulated Other Comprehensive Earnings, Beginning balance	-10.5
Other comprehensive income before reclassifications	-168.5
Amounts reclassified from accumulated other comprehensive income	-0.3													[1]
Tax effect of adjustments	47.1														13.6
Accumulated Other Comprehensive Earnings, Ending balance	($131.10)
[1]	The amortization of prior service cost is included in the computation of net periodic benefit cost. See NoteB 10 (Pension and Post-retirement Plans) below for additional information regarding the Company's net periodic benefit cost.

INCOME_TAXES_Details

INCOME TAXES (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Income Tax Disclosure [Abstract]
Minimum threshold percentage required to recognize income tax benefit (in hundredths)	50.00%
Gross unrecognized income tax benefits	$28.60	$16.70
Unrecognized income tax benefits that would impact effective tax rate	28.6	16.7
Accrued interest and penalties related to unrecognized income tax benefits	9.6	8.2
Valuation allowance provided for deferred tax assets	$16.80	$17.10

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Sep. 30, 2011	Jun. 30, 2011	Aug. 24, 2012
				Recipients
Loss Contingencies [Line Items]
Litigation settlement expense in connection with the California False Claims Act lawsuit			$34,500,000
Previously recorded litigation reserve in connection with the California False Claims Act lawsuit			15,000,000
Litigation Settlement, Gross		49.5
Payment reduction by Assembly Bill No. 97	10.00%
Percent of lowest maximum (cap on payments)	80.00%
Loss Contingency, Damages Awarded, Value	50,000,000
Loss Contingency Damages Awarded Gross	20,800,000
Number of Recipients				39
Proposed damages per violation				0.0005
Loss Contingency Damages Awarded Net	15,800,000
Reduction for Plaintiff Negligence	25.00%
Company's apportioned responsibility	50.00%
Co-defendant's apportioned responsibility	50.00%
Loss contingency reduced damages awarded gross	5,000,000
Loss contingency reduced damages awarded net	4,400,000
Letters of Credit Outstanding, Amount	$42,500,000
Tri-State Clinical Laboratory Services, LLC [Member]
Loss Contingencies [Line Items]
Ownership interest percentage, parent			50.00%
Minimum [Member]
Loss Contingencies [Line Items]
Proposed damages per violation	0
Maximum [Member]
Loss Contingencies [Line Items]
Proposed damages per violation	0

PENSION_AND_POSTRETIREMENT_PLA2

PENSION AND POSTRETIREMENT PLANS (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Plan Disclosures [Line Items]
Pension Contributions	$0
Minimum non-elective contribution (NEC) % for the 401(K) plan (in hundredths)	3.00%
Discretionary contribution % for the 401(K) plan, range mininum	1.00%
Discretionary contribution % for the 401(K) plan, range maximum	3.00%
Defined contribution retirement plan cost	12.9	13.4
Pension Plan [Member]
Defined Benefit Plan and Postretirement Plan Disclosure
Service cost for benefits earned	1	0.9
Interest cost on benefit obligation	3.8	3.9
Expected return on plan assets	-4.6	-4.4
Net amortization and deferral	2.7	1.8
Defined benefit/postretirement plan costs	2.9	2.2
Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosures [Line Items]
Defined Benefit Plan, Benefit Obligation	6.3
Defined Benefit Plan and Postretirement Plan Disclosure
Defined benefit/postretirement plan costs	0.2
Other Pension Plan, Postretirement or Supplemental Plans [Member]
Defined Benefit Plan and Postretirement Plan Disclosure
Service cost for benefits earned	0.3
Interest cost on benefit obligation	0.9
Expected return on plan assets	-1.3
Net amortization and deferral	0.2
Defined benefit/postretirement plan costs	0.1
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	0.00%
Defined Benefit Plan Expected Rate Of Return On Assets Other Assets	5.40%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase	0.00%
Other Pension Plan [Member]
Defined Benefit Plan and Postretirement Plan Disclosure
Service cost for benefits earned	0.1
Interest cost on benefit obligation	0
Expected return on plan assets	0
Net amortization and deferral	0.1
Defined benefit/postretirement plan costs	0.2
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	0.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase	2.00%
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosures [Line Items]
Defined Benefit Plan, Benefit Obligation	32.8
Defined Benefit Plan and Postretirement Plan Disclosure
Service cost for benefits earned	0.4
Interest cost on benefit obligation	0.9
Net amortization and deferral	0
Defined benefit/postretirement plan costs	1.3
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan and Postretirement Plan Disclosure
Service cost for benefits earned	0.1	0.1
Interest cost on benefit obligation	0.3	0.4
Net amortization and deferral	-2.4	-1.9
Defined benefit/postretirement plan costs	($2)	($1.40)

PENSION_AND_POSTRETIREMENT_PLA3

PENSION AND POSTRETIREMENT PLANS Defined Contribution Plans (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Non Elective Contribution	3.00%
Defined Contribution Plan, Cost Recognized	$12.90	$13.40
Covance [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	4.7
Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	$0.20

FAIR_VALUE_MEASUREMENTS_Detail

FAIR VALUE MEASUREMENTS (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Noncontrolling interest puts	$16.20	$17.70
Fair market value of zero-coupon subordinated notes	181.1	155.6
Fair market value of senior notes	6,586.80	2,949.80
Cash Surrender Value, Fair Value Disclosure	44.7	41.9
Fair Value Liabilities Measured On Recurring Basis Deferred Compensation Liability	43.1	43.4
Level 1 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Noncontrolling interest puts	0	0
Interest Rate Fair Value Hedge Asset at Fair Value	0	0
Cash Surrender Value, Fair Value Disclosure	0	0
Fair Value Liabilities Measured On Recurring Basis Deferred Compensation Liability	0	0
Level 2 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Noncontrolling interest puts	16.2	17.7
Interest Rate Fair Value Hedge Derivative at Fair Value, Net	34	18.5
Cash Surrender Value, Fair Value Disclosure	44.7	41.9
Fair Value Liabilities Measured On Recurring Basis Deferred Compensation Liability	43.1	43.4
Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Noncontrolling interest puts	0	0
Interest Rate Fair Value Hedge Derivative at Fair Value, Net	0	0
Cash Surrender Value, Fair Value Disclosure	0	0
Fair Value Liabilities Measured On Recurring Basis Deferred Compensation Liability	$0	$0

DERIVATIVE_INSTRUMENTS_AND_HED1

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Jan. 30, 2015	Nov. 19, 2010
	Embedded_Derivative_Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Debt Instrument, Face Amount	$600,000,000
Derivative, Basis Spread on Variable Rate	2.30%
Fair Value Hedges, Net	34,000,000		18,500,000
Number of features considered to be embedded derivative instruments	2
Minimum percentage of market price to calculated value of zero-coupon subordinated debt at which the entity is subject to contingent cash interest	120.00%
Embedded derivative, fair value	0
Embedded derivative, impact on condensed consolidated statements of operations	0	0
Senior notes due 2020 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.63%			2.63%	4.63%
Debt Instrument, Face Amount			$618,500,000

SUPPLEMENTAL_CASH_FLOW_INFORMA2

SUPPLEMENTAL CASH FLOW INFORMATION (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Debt Conversion [Line Items]
Noncash conversion of zero-coupon convertible debt	$0	$2.80
Fair Value of Assets Acquired	16.7	3.1
Increase (Decrease) in Accrued Liabilities	-1.4	4.7
Cash paid during period for:
Interest	14.9	18.8
Income taxes, net of refunds	23.1	8.6
Restricted Stock Awards And Performance Shares Surrendered	7.8	4.6
Other Significant Noncash Transaction, Value of Consideration Given	$1,762.50	$0

BUSINESS_ACQUISITIONS_Details

BUSINESS ACQUISITIONS (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Feb. 19, 2015	Jan. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 19, 2010
Business Acquisition [Line Items]
Net Income (Loss) Attributable to Parent	$0.70	$113.10
Total acquisition consideration (cash and non-cash)			6,150.70
Stock Issued During Period, Shares, Acquisitions	15,300,000
Senior Notes, Noncurrent				2,900
Business Combination, Acquisition Related Costs	166
Goodwill	6,282.20				3,099.40	3,022.80
Cash payments for laboratory-related assets	33.8	56.5
Payments to Acquire Businesses, Net of Cash Acquired	3,622.20	65.7
Selling, General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs	80.6
Cost of Goods, Total [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs	32.8
Interest Expense [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs	52.6
Covance [Member]
Business Acquisition [Line Items]
Net Income (Loss) Attributable to Parent	56.2
Total acquisition consideration (cash and non-cash)			6,150.70
Business Acquisition, Share Price			$75.76
Goodwill			3,176.10
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			0.2686
Excluding Covance [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	14.7
Finite-lived Intangible Assets Acquired	3.4
Use Rights [Member] | Covance [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	3 years
Senior notes due 2045 [Member]
Business Acquisition [Line Items]
Senior Notes, Noncurrent				900
Debt Instrument, Interest Rate, Stated Percentage				4.70%
Senior notes due 2020 [Member]
Business Acquisition [Line Items]
Senior Notes, Noncurrent	$500			$500	$0
Debt Instrument, Interest Rate, Stated Percentage	4.63%			2.63%			4.63%

BUSINESS_ACQUISITIONS_Business

BUSINESS ACQUISITIONS Business Acquisitions in the Aggregate (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Feb. 19, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Other Significant Noncash Transaction, Value of Consideration Given	$1,762,500,000	$0
Total acquisition consideration (cash and non-cash)			6,150,700,000
Other Long-term Debt	925,000,000			0
Revenues	1,793,200,000	1,430,700,000
Payments to Acquire Businesses, Net of Cash Acquired	3,622,200,000	65,700,000
Goodwill, Acquired During Period	3,187,600,000	81,800,000
Unbilled Receivables, Current	72,400,000
Goodwill	6,282,200,000			3,099,400,000	3,022,800,000
Covance [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	207,600,000
Post combination acceleration of stock compensation expense	43,200,000
Employer taxes on accelerated equity	9,400,000
Make-whole payment	37,400,000
Cash paid for acquisition			4,388,200,000
Other Significant Noncash Transaction, Value of Consideration Given	1,762,500,000
Total acquisition consideration (cash and non-cash)			6,150,700,000
Cash consideration			780,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent			730,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt			250,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable			190,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities			280,800,000
Deferred Revenue			168,000,000
Other Long-term Debt			1,000,000,000,000
Revenues	267,200,000
Revenues	2,146,400,000	2,097,000,000
Net Income (Loss) Attributable to Parent	110,400,000	-25,100,000
Cash on Hand Used for Acquisition			488,200,000
Acquisition Financing			3,900,000,000,000
Other long term debt acquistion financing			400,000,000
Accounts receivable			334,800,000
Unbilled Receivables, Current			138,700,000
Inventories			51,900,000
Prepaid expenses and other			261,400,000
Deferred income taxes			34,400,000
Property, plant and equipment			844,200,000
Goodwill			3,176,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets			15,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other			78,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			1,698,300,000
Operating income	250,100,000	78,600,000
Basic	$1,090,000	($250,000)
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$1,080,000	($250,000)
Covance, Inc. [Member]
Business Acquisition [Line Items]
Change in control and severance payments	26,800,000
Legal Fees	75,600,000
Write off of bridge and other deferred financing costs	15,200,000
Excluding Covance [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	14,700,000
Finite-lived Intangible Assets Acquired	3,400,000
Goodwill, Acquired During Period	11,500,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	27 years
Customer Relationships [Member] | Covance [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			1,917,200,000
Trademarks and Trade Names [Member] | Covance [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	15 years
Trade Names [Member] | Covance [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			289,400,000
Use Rights [Member] | Covance [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	3 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			$4,900,000

BUSINESS_SEGMENT_INFORMATION_B1

BUSINESS SEGMENT INFORMATION Business Segment Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Total net revenues	$1,772.30	$1,430.70
Reimbursement Revenue	20.9	0
Revenues	1,793.20	1,430.70
Total operating income	130.2	203.3
Non-operating expenses, net	-99.9	-15.6
Earnings before income taxes	30.3	187.7
Provision for income taxes	29.3	74.2
Net earnings	1	113.5
Less income attributable to noncontrolling interests	-0.3	-0.4
Net income attributable to Laboratory Corporation of America Holdings	0.7	113.1
LabCorp Diagnostics [Member]
Segment Reporting Information [Line Items]
Total net revenues	1,472	1,392.90
Total operating income	222.8	232.3
General corporate expenses [Member]
Segment Reporting Information [Line Items]
Total operating income	-38.2	-33.5
Covance Drug Development [Member]
Segment Reporting Information [Line Items]
Total net revenues	300.3	37.8
Reimbursement Revenue	20.9	0
Total operating income	($54.40)	$4.50

Uncategorized_Items

Uncategorized Items
[us-gaap_StockholdersEquity]	45,500,000	0	10,400,000	3,408,900,000	-963,500,000