Accounts receivable, net of allowance for doubtful accounts of $173.1 and $161.0 at December 31, 2009 and 2008, respectively Accumulated other comprehensive income (loss) Acquisition of businesses, net of cash acquired Acquisition of businesses, net of cash acquired Additional paid-in capital Allowance for doubtful accounts Amortization of intangibles and other assets Cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period (Increase) decrease in accounts receivable (net) Increase (decrease) in bank overdraft (Increase) decrease in inventories (Increase) decrease in prepaid expenses and other Change in assets and liabilities (net of effects of acquisitions): Increase in accounts payable COMMITMENTS AND CONTINGENT LIABILITIES Common stock, shares outstanding (in shares) Common stock, 105.3 and 108.2 shares outstanding at December 31, 2009 and 2008, respectively Comprehensive earnings Comprehensive earnings Cost of sales Current liabilities: Total current liabilities Total current liabilities Short-term borrowings and current portion of long-term debt DEBT Deferred income taxes Deferred Income Tax Expense Benefit DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Diluted earnings per common share (in dollars per share) Income from joint venture partnerships, net Effect of exchange rate changes on cash and cash equivalents Stock compensation Share Based Compensation Loss on sale of assets Gross profit Gross Profit INCOME TAXES Intangible assets, net Interest expense Supplies inventories Investment income Investments in joint venture partnerships LIABILITIES AND SHAREHOLDERS' EQUITY Total liabilities and shareholders' equity Total liabilities and shareholders' equity Total liabilities Total liabilities Long-term debt, less current portion NONCONTROLLING INTEREST PUT Noncontrolling interest CASH FLOWS FROM FINANCING ACTIVITIES: Net cash used for financing activities Net cash used for financing activities CASH FLOWS FROM INVESTING ACTIVITIES: Net cash used for investing activities Net cash used for investing activities CASH FLOWS FROM OPERATING ACTIVITIES: Net cash provided by operating activities Net cash provided by operating activities Net earnings attributable to Laboratory Corporation of America Holdings Net earnings attributable to Laboratory Corporation of America Holdings Net increase (decrease) in cash and cash equivalents Net decrease in cash and cash equivalents NEW ACCOUNTING PRONOUNCEMENTS Other income (expenses): Operating income Operating Income Loss BASIS OF FINANCIAL STATEMENT PRESENTATION Interest rate swap adjustments Foreign currency translation adjustments Other comprehensive earnings: Tax effect of other comprehensive earnings adjustments Tax effect of other comprehensive earnings adjustments Tax effect of other comprehensive earnings adjustments Other, net Noncontrolling interest distributions Noncontrolling interest distributions PENSION AND POSTRETIREMENT PLANS Prepaid expenses and other Proceeds from revolving credit facilities Proceeds from sale of assets Proceeds from sale of short-term investments Property, plant and equipment, net Investment in equity affiliate Investment in equity affiliate Acquisition of licensing technology Acquisition of licensing technology Capital expenditures Capital expenditures Purchases of short-term investments Purchases of short-term investments Payments on revolving credit facilities Payments on revolving credit facilities Principal payments on term loan Principal payments on term loan Purchase of common stock Payments For Repurchase Of Common Stock RESTRUCTURING AND OTHER SPECIAL CHARGES [Abstract] Restructuring and other special charges Retained earnings Net sales PROPOSED ACQUISITION Selling, general and administrative expenses Shareholders' equity GOODWILL AND INTANGIBLE ASSETS SUPPLEMENTAL CASH FLOW INFORMATION [Abstract] Current assets: Total current assets Total current assets Treasury Stock Common Stock Total assets Total assets Other liabilities RESTRUCTURING AND OTHER SPECIAL CHARGES Deferred income taxes Deferred Tax Assets Net Current Cumulative earnings less than (in excess of) distribution from joint venture partnerships ASSETS FAIR VALUE MEASUREMENTS Less common stock held in treasury Less common stock held in treasury SUPPLEMENTAL CASH FLOW INFORMATION Basic earnings per common share (in dollars per share) Excess tax benefits from stock based compensation Other assets, net EARNINGS PER SHARE [Abstract] RESTRUCTURING RESERVES Total shareholders' equity BALANCE BALANCE Total shareholders' equity Provision for income taxes Comprehensive earnings: Additional Paid-in Capital Retained Earnings Accumulated Other Comprehensive (Loss) Income Goodwill, net Surrender of restricted stock awards and performance shares Purchase of common stock Stock Repurchased During Period Value Income tax benefit from stock options exercised EARNINGS PER SHARE Earnings Per Share [Text Block] Net earnings Net earnings Less: Net earnings attributable to the noncontrolling interest Less: Net earnings attributable to the noncontrolling interest Depreciation and amortization Accounts payable Accrued expenses and other Commitments and contingent liabilities Adjustments to reconcile net earnings to net cash provided by operating activities: Stock compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value BASIS OF FINANCIAL STATEMENT PRESENTATION [Abstract] RESTRUCTURING RESERVES [Abstract] BAD DEBT EXPENSE [Abstract] BAD DEBT EXPENSE Disclosure in connection with an increase in the Company's provision for doubtful accounts. Bad Debt Expense [Text Block] NONCONTROLLING INTEREST PUT [Abstract] GOODWILL AND INTANGIBLE ASSETS [Abstract] DEBT [Abstract] PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY [Abstract] PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY Disclosure of authorized shares and par value of common and preferred stock. Reporting of changes in common shares and held in treasury is also included in this disclosure. Purchases of the Company's common stock is disclosed under its Shares Repurchase Program. PREFERRED STOCK AND COMMON SHAREHOLDERS' EQUITY [Text Block] INCOME TAXES [Abstract] NEW ACCOUNTING PRONOUNCEMENTS [Abstract] COMMITMENTS AND CONTINGENCIES [Abstract] PENSION AND POSTRETIREMENT PLANS [Abstract] FAIR VALUE MEASUREMENTS [Abstract] DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES [Abstract] PROPOSED ACQUISITION [Abstract] Earnings before income taxes Sum of operating profit and nonoperating income (expense) before income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest. Earnings before income taxes Income Loss from Continuing Operations Before Income Taxes and Minority Interest Accreted interest on zero-coupon subordinated notes This element represents the accreted interest on zero-coupon subordinated notes. Deferred payments on acquisitions This element represents deferred payments (payments on accrued acquisition related liabilities) on acquisitions. Payments on zero-coupon subordinated notes The cash outflow (payments) on the zero-coupon subordinated notes. Payments on vendor-financed equipment The cash outflow (payments) on vendor-financed equipment. Net proceeds from issuance of stock to employees The cash inflow associated with the amount received from holders exercising their stock options and employees related to shares purchased under the employee stock purchase plan. PROPOSED ACQUISITION Disclosure of proposed significant event (business combination) expected to occur in the next quarter (third quarter of 2009). Proposed Acquisition [Text Block] Deferred income taxes and other tax liabilities Represents the noncurrent portion of deferred tax liabilities, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax, combined with the noncurrent portion of the amount recognized for uncertain tax positions as of the balance sheet date. A noncurrent taxable temporary difference is a difference between the tax basis and the carrying amount of a noncurrent asset or liability in the financial statements prepared in accordance with generally accepted accounting principles. In a classified statement of financial position, an enterprise shall separate deferred tax liabilities and assets into a current amount and a no ncurrent amount. Deferred tax liabilities and assets shall be classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, shall be classified according to the expected reversal date of the temporary difference. Aggregate change in value for stock issued during the period as a result of employee stock purchase plan, combined the value of stock issued during the period as a result of the exercise of stock options. Issuance of common stock under employee stock plans Conversion of zero-coupon convertible debt Value of stock issued during the period upon the conversion of convertible securities (zero-coupon subordinated notes) and/or reversal of deferred tax liability to reflect the tax benefit realized upon issuance of the stock. Value of noncontrolling interest put Change in additional paid-in capital as a result of the initial difference between the value of the put and the underlying noncontrolling interest being recorded as additional noncontrolling interest and as a reduction to additional paid-in capital. Decrease In Accrued Expenses And Other The net change during the reporting period in the aggregate amount of expenses incurred but not yet paid and the net change during the reporting period in the value of other assets or liabilities used in operating activities. Increase (decrease) in accrued expenses and other Payments on long-term debt Payments on long-term debt BUSINESS ACQUISITIONS Statement of Stockholders' Equity [Abstract] Statement [Table] Statement, Equity Components [Axis] Equity Component [Domain] Statement [Line Items] BUSINESS ACQUISITIONS [ABSTRACT] Document Type Amendment Flag Amendment Description Document Period End Date Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding