BASIS OF FINANCIAL STATEMENT PRESENTATION	3 Months Ended
Mar. 31, 2016
Accounting Policies [Abstract]
Basis of Financial Statement Presentation	BASIS OF FINANCIAL STATEMENT PRESENTATION Laboratory Corporation of America Holdings together with its subsidiaries (Company) is the world’s leading healthcare diagnostics company, providing comprehensive clinical laboratory services and end-to-end drug development support. The Company’s strategic vision is to improve health and improve lives by delivering world class diagnostic solutions, bringing innovative medicines to patients faster, and changing the way care is provided through the deployment of technology-enabled solutions. The Company serves managed care organizations (MCOs), biopharmaceutical companies, governmental agencies, physicians, hospitals and health systems, employers, patients and consumers, food and nutritional companies and independent clinical laboratories. The Company believes that it generated more revenue from laboratory testing than any other company in the world in 2015. The Company reports its business in two segments, LabCorp Diagnostics (LCD) and Covance Drug Development (CDD). For further financial information about these segments, see Note 14 (Business Segment Information). During the three months ended March 31, 2016, LCD and CDD contributed 69.3% and 30.7%, respectively, of net revenues to the Company. The condensed consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries for 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 operating 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. 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 2015 Annual Report on Form 10-K, as amended. Therefore, the interim statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report. New Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (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. On July 9, 2015, the FASB approved the proposal to defer the effective date of this standard by one year. 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 November 2015, the FASB issued a new accounting standard that requires the deferred tax liabilities and assets to be classified as noncurrent on the consolidated balance sheet. The Company early adopted this standard on a full-retrospective basis as of March 31, 2016. The adoption of this standard does not have a material impact on the consolidated financial statements. In January 2016, the FASB issued a new accounting standard that addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. A financial instrument is defined as cash, evidence of ownership interest in a company or other entity, or a contract that both: (i) imposes on one entity a contractual obligation either to deliver cash or another financial instrument to a second entity or to exchange other financial instruments on potentially unfavorable terms with the second entity and (ii) conveys to that second entity a contractual right either to receive cash or another financial instrument from the first entity or to exchange other financial instruments on potentially favorable terms with the first entity. The standard will be effective for the Company beginning January 1, 2018, with early adoption permitted. The Company is evaluating the impact that this new standard will have on the consolidated financial statements. In February 2016, the FASB issued a new accounting standard that sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for based on guidance similar to current guidance for operating leases. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The standard is effective on January 1, 2019, with early adoption permitted. The Company is evaluating the impact that this new standard will have on the consolidated financial statements. In March 2016, the FASB issued a new accounting standard intended to simplify aspects of share-based payment accounting. The standard changes how companies account for certain aspects of share-based payment awards to employees, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as the classification of related matters in the statement of cash flows. The update is effective on January 1, 2017, with early adoption permitted. The Company is currently evaluating this new standard and the impact it will have on its consolidated financial statements. Reclassifications The Company has reclassified debt issuance costs from prepaid and other assets, net to direct deductions from the associated debt liability in the December 31, 2015 consolidated balance sheet in accordance with the implementation of a recently issued FASB standard update. In addition, the Company has reclassified short-term deferred tax assets and short-term deferred tax liabilities to net long-term deferred tax assets and net long-term deferred tax liabilities by jurisdiction, respectively, in the December 31, 2015 consolidated balance sheet in accordance with the implementation of a recently issued FASB standard update.

BASIS OF FINANCIAL STATEMENT PRESENTATION

Laboratory Corporation of America Holdings together with its subsidiaries (Company) is the world’s leading healthcare diagnostics company, providing comprehensive clinical laboratory services and end-to-end drug development support. The Company’s strategic vision is to improve health and improve lives by delivering world class diagnostic solutions, bringing innovative medicines to patients faster, and changing the way care is provided through the deployment of technology-enabled solutions. The Company serves managed care organizations (MCOs), biopharmaceutical companies, governmental agencies, physicians, hospitals and health systems, employers, patients and consumers, food and nutritional companies and independent clinical laboratories. The Company believes that it generated more revenue from laboratory testing than any other company in the world in 2015.

The Company reports its business in two segments, LabCorp Diagnostics (LCD) and Covance Drug Development (CDD). For further financial information about these segments, see Note 14 (Business Segment Information). During the three months ended March 31, 2016, LCD and CDD contributed 69.3% and 30.7%, respectively, of net revenues to the Company.

The condensed consolidated financial statements include the accounts of the Company and its majority-owned subsidiaries for 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 operating 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.

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 2015 Annual Report on Form 10-K, as amended. Therefore, the interim statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report.

New Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (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. On July 9, 2015, the FASB approved the proposal to defer the effective date of this standard by one year. 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 November 2015, the FASB issued a new accounting standard that requires the deferred tax liabilities and assets to be classified as noncurrent on the consolidated balance sheet. The Company early adopted this standard on a full-retrospective basis as of March 31, 2016. The adoption of this standard does not have a material impact on the consolidated financial statements.

In January 2016, the FASB issued a new accounting standard that addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. A financial instrument is defined as cash, evidence of ownership interest in a company or other entity, or a contract that both: (i) imposes on one entity a contractual obligation either to deliver cash or another financial instrument to a second entity or to exchange other financial instruments on potentially unfavorable terms with the second entity and (ii) conveys to that second entity a contractual right either to receive cash or another financial instrument from the first entity or to exchange other financial instruments on potentially favorable terms with the first entity. The standard will be effective for the Company beginning January 1, 2018, with early adoption permitted. The Company is evaluating the impact that this new standard will have on the consolidated financial statements.

In February 2016, the FASB issued a new accounting standard that sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for based on guidance similar to current guidance for operating leases. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The standard is effective on January 1, 2019, with early adoption permitted. The Company is evaluating the impact that this new standard will have on the consolidated financial statements.

In March 2016, the FASB issued a new accounting standard intended to simplify aspects of share-based payment accounting. The standard changes how companies account for certain aspects of share-based payment awards to employees, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as the classification of related matters in the statement of cash flows. The update is effective on January 1, 2017, with early adoption permitted. The Company is currently evaluating this new standard and the impact it will have on its consolidated financial statements.

Reclassifications

The Company has reclassified debt issuance costs from prepaid and other assets, net to direct deductions from the associated debt liability in the December 31, 2015 consolidated balance sheet in accordance with the implementation of a recently issued FASB standard update.

In addition, the Company has reclassified short-term deferred tax assets and short-term deferred tax liabilities to net long-term deferred tax assets and net long-term deferred tax liabilities by jurisdiction, respectively, in the December 31, 2015 consolidated balance sheet in accordance with the implementation of a recently issued FASB standard update.