Organization and Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2012
Accounting Policies [Abstract]
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation The consolidated financial statements include the accounts of Level 3 Communications, Inc. and subsidiaries in which it has a controlling interest. Prior to the disposition of the coal mining business during the fourth quarter of 2011, the Company's 50% owned mining joint ventures were consolidated on a pro rata basis. All significant intercompany accounts and transactions have been eliminated. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). As part of its consolidation policy, the Company considers its controlled subsidiaries, investments in businesses in which the Company is not the primary beneficiary or does not have effective control but has the ability to significantly influence operating and financial policies, and variable interests resulting from economic arrangements that give the Company rights to economic risks or rewards of a legal entity. The Company does not have variable interests in a variable interest entity where it is required to consolidate the entity as the primary beneficiary or where it has concluded it is not the primary beneficiary.
Foreign Currency Translation	Foreign Currency Translation Local currencies of foreign subsidiaries are the functional currencies for financial reporting purposes except for certain foreign subsidiaries in Latin America. For operations outside the U.S. that have functional currencies other than the U.S. dollar, assets and liabilities are translated to U.S. dollars at period-end exchange rates, and revenue, expenses and cash flows are translated using average exchange rates prevailing during the year. Gains or losses resulting from currency translation are recorded as a component of accumulated other comprehensive loss in stockholders' equity (deficit) and in the consolidated statements of comprehensive loss. A significant portion of the Company's foreign subsidiaries have either the British Pound or the Euro as the functional currency, both of which experienced significant fluctuations against the U.S. dollar during 2012, 2011 and 2010. As a result of the Amalgamation during the fourth quarter of 2011, the Company also is exposed to fluctuations in the Brazilian Real. The Company has experienced significant foreign currency translation adjustments that are recognized as a component of accumulated other comprehensive income (loss) in stockholders' equity (deficit) and in the consolidated statement of comprehensive loss in accordance with accounting guidance for foreign currency translation. The Company considers the majority of its investments in its foreign subsidiaries to be long-term in nature. The Company's foreign exchange transaction gains (losses), including where its investments in its foreign subsidiaries are not considered to be long-term in nature, are included within other income (expense) on the consolidated statement of operations.
Reclassifications	Reclassifications Certain immaterial reclassifications have been made to prior years to conform to the current period's presentation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reported period. The accounting estimates that require management's judgments include revenue recognition, revenue reserves, cost of revenue for communications services, the determination of the useful lives of long-lived assets, the valuation and recognition of stock-based compensation expense, the valuation of long-lived assets, goodwill and acquired indefinite-lived intangible assets, derivative financial instruments, the valuation of asset retirement obligations, the allowance for doubtful accounts, the recognition of the fair value of assets acquired and liabilities assumed in business combinations, accruals for estimated tax and legal liabilities, valuation allowance for deferred tax assets, and valuation of other assets and liabilities measured at fair value. Actual results could differ from these estimates under different assumptions or conditions and such differences could be material.
Revenue and Cost of Revenue for Communications Services	Revenue and Cost of Revenue for Communications Services Revenue for communications services is recognized monthly as the services are provided based on contractual amounts expected to be collected. Management establishes appropriate revenue reserves at the time services are rendered based on an analysis of historical credit activity to address, where significant, situations in which collection is not reasonably assured as a result of credit risk, potential billing disputes or other reasons. Actual results may differ from these estimates under different assumptions or conditions and such differences could be material. Intercarrier compensation revenue is recognized when an interconnection agreement is in place with another carrier, or if an agreement has expired, when the parties have agreed to continue operating under the previous agreement until a new agreement is negotiated and executed, or at rates mandated by the FCC. For certain sale and long-term indefeasible right of use, or IRU, contracts involving private line, wavelengths and dark fiber services, the Company may receive up-front payments for services to be delivered for a period of up to 25 years. In these situations, the Company defers the revenue and amortizes it on a straight-line basis to earnings over the term of the contract. Termination revenue is recognized when a customer discontinues service prior to the end of the contract period for which Level 3 had previously received consideration and for which revenue recognition was deferred. Termination revenue also is recognized when customers are required to make termination penalty payments to Level 3 to settle contractually committed purchase amounts that the customer no longer expects to meet or when a customer and Level 3 renegotiate a contract under which Level 3 is no longer obligated to provide services for consideration previously received and for which revenue recognition has been deferred. The Company is obligated under dark fiber IRUs and other capacity agreements to maintain its network in efficient working order and in accordance with industry standards. Customers are obligated for the term of the agreement to pay for their allocable share of the costs for operating and maintaining the network. The Company recognizes this revenue monthly as services are provided. Level 3's customer contracts require the Company to meet certain service level commitments. If Level 3 does not meet the required service levels, it may be obligated to provide credits, usually in the form of free service, for a short period of time. The credits are a reduction to revenue and, to date, have not been material. Cost of revenue for the communications business includes leased capacity, right-of-way costs, access charges, satellite transponder lease costs and other third party costs directly attributable to the network, but excludes depreciation and amortization and related impairment expenses. The Company recognizes the cost of network services as they are incurred in accordance with contractual requirements. The Company disputes incorrect billings from its suppliers of network services. The most prevalent types of disputes include disputes for circuits that are not disconnected by the supplier on a timely basis and usage bills with incorrect or inadequate information. Depending on the type and complexity of the issues involved, it may and often does take several quarters to resolve the disputes. The Company establishes appropriate cost of revenue reserves for disputed supplier billings based on an analysis of historical experience in resolving disputes with its suppliers. In determining the amount of the cost of network service expenses and related accrued liabilities to reflect in its financial statements, the Company considers the adequacy of documentation of disconnect notices, compliance with prevailing contractual requirements for submitting these disconnect notices and disputes to the provider of the network services, and compliance with its interconnection agreements with these carriers. Judgment is required in estimating the ultimate outcome of the dispute resolution process, as well as any other amounts that may be incurred to conclude the negotiations or settle any litigation. Actual results may differ from these estimates under different assumptions or conditions and such differences could be material.
Coal Mining	Coal Mining Prior to the sale of its coal mining business in November 2011, the Company sold coal primarily through long-term contracts with public utilities. The long-term contracts for the delivery of coal established the price, volume, and quality requirements of the coal to be delivered. Revenue under these and other contracts was generally recognized when coal was shipped to the customer.
USF and Gross Receipts Taxes	USF and Gross Receipts Taxes The revenue recognition standards include guidance relating to any tax assessed by a governmental authority that is directly imposed on a revenue-producing transaction between a seller and a customer and may include, but is not limited to, gross receipts taxes and certain state regulatory fees. The Company records Universal Service Fund ("USF") contributions where the Company is the primary obligor for the taxes assessed in each jurisdiction where it does business on a gross basis in its consolidated statements of operations, but generally records gross receipts taxes and certain state regulatory fees billed to its customers on a net basis in its consolidated statements of operations. Communications revenue and cost of revenue on the consolidated statements of operations includes USF contributions totaling $191 million, $107 million and $77 million for the years ended December 31, 2012, 2011 and 2010, respectively.
Advertising Costs	Advertising Costs The Company expenses the cost of advertising as incurred. Advertising expense is included as a component of selling, general and administrative expenses in the accompanying consolidated statements of operations. Advertising expense was $20 million, $15 million and $8 million for the years ended December 31, 2012, 2011 and 2010, respectively.
Share-Based Compensation	Stock-Based Compensation The Company recognizes the estimated fair value of stock based compensation costs, net of an estimated forfeiture rate, over the requisite service period of the award, which is generally the vesting term or term for restrictions on transfer that lapse, as the case may be. The Company funded a portion of its 2012, 2011 and 2010 discretionary bonus in stock awards that were vested upon issuance. The Company estimates forfeiture rates based on its historical experience for the type of award.
Income Taxes	Income Taxes The Company recognizes deferred tax assets and liabilities for its domestic and foreign operations, for the expected tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts using enacted tax rates in effect for the year the differences are expected to reverse. The Company records a valuation allowance to reduce the deferred tax assets to the amount that is more likely than not to be realized. The Company recognizes interest and penalty expense associated with uncertain tax positions as a component of income tax expense in the consolidated statements of operations.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company classifies investments as cash equivalents if they are readily convertible to cash and have original maturities of three months or less at the time of acquisition. Cash and cash equivalents consist primarily of highly liquid investments in government and government agency securities and money market funds issued or managed by financial institutions in the U.S., Europe and Latin America and commercial paper depending on liquidity requirements. As of December 31, 2012 and 2011, the carrying value of cash and cash equivalents approximates fair value due to the short period of time to maturity.
Restricted Cash and Securities	Restricted Cash and Securities Restricted cash and securities consists primarily of cash and investments that serve to collateralize outstanding letters of credit and certain performance and operating obligations of the Company. Restricted cash and securities are recorded as current or non-current assets in the consolidated balance sheets depending on the duration of the restriction and the purpose for which the restriction exists. Restricted cash and securities are stated at cost which approximates fair value as of December 31, 2012 and 2011.
Derivatives Financial Instruments	Derivative Financial Instruments All derivative instruments are measured at fair value and recognized as either assets or liabilities on the Company's consolidated balance sheets. The Company's derivative instruments are valued primarily using models based on readily observable market parameters for all substantial terms of the Company's derivative contracts and thus are classified as Level 2 of the GAAP fair value hierarchy (see Note 10 - Fair Value of Financial Instruments). The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation. For derivative instruments designated as cash flow hedges, the effective portion of the derivative's gain (loss) is initially reported as a component of Accumulated Other Comprehensive Income (Loss) ("AOCI") and is subsequently recognized in earnings in the period the hedged transaction affects earnings or when they are no longer effective. Gains (losses) resulting from hedge ineffectiveness and those resulting from changes in fair values on derivatives not designated as hedging instruments are recognized in other income (expense) in the consolidated statements of operations (see Note 11 - Derivative Financial Instruments).
Allowance for Doubtful Accounts	Allowance for Doubtful AccountsTrade accounts receivable are recorded at the invoiced amount and can bear interest. The Company establishes an allowance for doubtful accounts for accounts receivable amounts that may not be collectible. The Company determines the allowance for doubtful accounts based on the aging of its accounts receivable balances and an analysis of its historical experience of bad debt write-offs. The Company reviews its allowance for doubtful accounts quarterly. Accounts receivable balances are written off against the allowance for doubtful accounts after all means of collection have been exhausted and the potential for recovery is considered remote. The Company recognized bad debt expense, net of recoveries, of approximately $15 million in 2012, $6 million in 2011 and $16 million in 2010.
Property, Plant and Equipment	In connection with the acquisition of Global Crossing in 2011, the Company evaluated the estimated useful lives of its fixed assets and determined that the period it expected to use conduit, fiber, and certain transmission equipment was longer than the remaining originally estimated useful lives. The Company revised its estimated useful lives of conduit from its historical estimate of 25 years to a revised estimate of 50 years; of fiber from its historical estimate of 12 years to a revised estimate of 25 years ; and of certain transmission equipment from its historical estimate of 7 years to its revised estimate of 15 years. In determining the change in estimated useful lives, the Company, with input from its engineering team, considered its historical usage patterns and retirements, estimates of technological obsolescence, and expected usage and maintenance. Property, Plant and Equipment Property, plant and equipment are recorded at cost. Leasehold improvements are depreciated over the shorter of their estimated useful lives or lease terms that are reasonably assured. The Company capitalizes costs directly associated with expansions and improvements of the Company's communications network and customer installations, including employee-related costs, and generally capitalizes costs associated with network construction and provisioning of services. The Company amortizes such costs over an estimated useful life of 3 to 7 years. In addition, the Company continues to develop business support systems required for its business. The external direct costs of software, materials and services, and payroll and payroll-related expenses for employees directly associated with business support systems projects are capitalized. Upon the completion of a project, the total cost of the business support system is amortized over an estimated useful life of 3 years.
Asset Retirement Obligations	Asset Retirement Obligations The Company recognizes a liability for the estimated fair value of legal obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or the normal operation of a long-lived asset in the period incurred. The fair value of the obligation is also capitalized as property, plant and equipment and then amortized over the estimated remaining useful life of the associated asset. Increases to the asset retirement obligation liability due to the passage of time are recognized as accretion expense and included within selling, general and administrative expenses and within income (loss) from discontinued operations for reclamation associated with the coal mining business on the Company's consolidated statements of operations prior to the sale of the coal mining business in November 2011. Changes in the liability due to revisions to the amount or timing of future cash flows are recognized by increasing or decreasing the liability with the offset adjusting the carrying amount of the related long-lived asset. To the extent that the downward revisions exceed the carrying amount of the related long-lived asset initially recorded when the asset retirement obligation liability was established, the Company records the remaining adjustment as a reduction to depreciation expense, to the extent of historical depreciation of the related long-lived asset, and then to selling, general and administrative expense.
Goodwill and Acquired Indefinite-Lived Intangible Assets	Goodwill and Acquired Indefinite-Lived Intangible Assets Accounting guidance prohibits the amortization of goodwill and purchased intangible assets with indefinite useful lives. The Company reviews goodwill and purchased intangible assets with indefinite lives for impairment annually at the end of the fourth quarter and whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable. The Company's goodwill impairment review process considers the fair value of each reporting unit relative to its carrying value. If the fair value of the reporting unit exceeds its carrying value, goodwill is not impaired and no further testing is performed. If the carrying value of the reporting unit exceeds its fair value, then a second step must be performed, and the implied fair value of the reporting unit's goodwill must be determined and compared to the carrying value of the reporting unit's goodwill. If the carrying value of a reporting unit's goodwill exceeds its implied fair value, then an impairment loss equal to the difference will be recorded. Beginning with the 2011 assessment in accordance with updated accounting guidance, prior to performing the two step evaluation, an assessment of qualitative factors may be performed to determine whether it is more likely than not that the fair value of a reporting unit exceeds the carrying value. If it is determined that it is unlikely that the carrying value exceeds the fair value, the Company is not required to complete the two step goodwill impairment evaluation. In 2012, the Company's reporting units consist of its three regional operating units in: North America; Europe, the Middle East and Africa ("EMEA"); and Latin America. In 2011, the Company's reporting units were consistent with its reportable segments of Level 3 and Global Crossing, representing the stand-alone operations of each legacy business. In 2010, the Company's reporting units were consistent with its reportable segments of communications and coal mining. In 2012 and 2011, the Company conducted its assessment of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit exceeds the carrying value. During 2010, the Company considered the use of multiple valuation techniques in accordance with GAAP Fair Value Measurements and Disclosures guidance to estimate the fair value of its reporting units and had consistently applied a market approach as part of its impairment assessment process. Under the market approach, the Company estimated the fair value using an in-exchange valuation premise based upon the market capitalization of Level 3 using quoted market prices, added an estimated control premium, and then assigned that fair market value to the reporting units. The Company's indefinite-lived intangibles assets impairment review process compares the fair value of the indefinite-lived intangible assets to their respective carrying values. If the fair value of the indefinite-lived intangible assets exceeds their carrying values, then the indefinite-lived intangible assets are not impaired. If the carrying value of the indefinite-lived intangible assets exceeds their fair value, then an impairment loss equal to the difference will be recorded. In accordance with recently issued accounting guidance, an entity may assess qualitative factors to determine whether it is more likely than not that the fair value exceeds the carrying value prior to performing the two step evaluation. If it is determined that it is unlikely the carrying value exceeds the fair value, then the entity is no longer required to complete the two step indefinite-lived intangible assets impairment evaluation. In 2012, the Company conducted its indefinite-lived intangible assets impairment analysis using the qualitative assessment to determine whether it is more likely than not that the fair value of its indefinite-lived intangible assets exceeds the carrying value. In 2011 and 2010, the Company estimated the fair value of its indefinite-lived intangible assets primarily utilizing an income approach. The Company recognizes an impairment loss when the estimated fair value of the indefinite-lived intangible assets is less than the carrying value. The Company conducted its goodwill and acquired indefinite-lived intangible assets impairment analysis at the end of 2012, 2011 and 2010 and in each case concluded that its goodwill was not impaired in any of those periods. The Company conducted its indefinite-lived intangible asset impairment analysis at the end of 2012 and 2010 and concluded that there was no impairment. During 2011, the Company determined that the carrying value of certain wireless spectrum licenses that it acquired in a prior acquisition was impaired and the Company recognized a $20 million charge in the fourth quarter that was recognized in Other Expense. The Company concluded that its remaining indefinite-lived intangible assets were not impaired as of December 31, 2011.
Long-Lived Assets Including Finte-Lived Purchased Intangible Assets	Long-Lived Assets Including Finite-Lived Purchased Intangible Assets The Company amortizes acquired intangible assets with finite lives using the straight-line method over the estimated economic lives of the assets, ranging from 4 to 12 years.
Impairment of Finite Lived Intangible Assets and Property Plant and Equipment	The Company evaluates long-lived assets, such as property, plant and equipment and acquired intangible assets with finite lives, for impairment whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable. The Company assesses the recoverability of the assets based on the undiscounted future cash flows the asset groups are expected to generate and recognizes an impairment loss when estimated undiscounted future cash flows expected to result from the use of the assets plus net proceeds expected from disposition of the assets, if any, are less than the carrying value of the assets. If an asset is deemed to be impaired, the amount of the impairment loss is the excess of the asset's carrying value over its estimated fair value.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash equivalents, accounts receivable, restricted cash and securities and derivatives. The Company maintains its cash equivalents, restricted cash and securities and derivatives with various financial institutions. These financial institutions are primarily located in the United States, Europe and Latin America and the Company's policy is to limit exposure with any one institution. As part of its cash and risk management processes, the Company performs periodic evaluations of the relative credit standing of the financial institutions. The Company also has established guidelines relative to financial instrument credit ratings, diversification and maturities that seek to maintain safety and liquidity. The Company's investment strategy generally results in lower yields on investments but reduces the risk to principal in the short term prior to these funds being used in the Company's business. The Company has not experienced any material losses on financial instruments held at financial institutions. From time to time, the Company utilizes interest rate swap contracts to protect against the effects of interest rate fluctuations. Such contracts involve the risk of non-performance by the counterparty, which could result in a material loss. The Company provides communications services to a wide range of wholesale and enterprise customers, ranging from well capitalized national carriers to small early stage companies primarily in the United States, Europe, and Latin America. Credit risk with respect to accounts receivable is generally diversified due to the large number of entities comprising Level 3's customer base and their dispersion across many different industries and geographical regions. The Company performs ongoing credit evaluations of its customers' financial condition and generally requires no collateral from its customers, although letters of credit and deposits are required in certain limited circumstances. The Company has from time to time entered into agreements with value-added resellers and other channel partners to reach consumer and enterprise markets for voice services. The Company has policies and procedures in place to evaluate the financial condition of these resellers prior to initiating service to the final customer. The Company maintains an allowance for doubtful accounts based upon the expected collectability of accounts receivable. Due to the Company's credit evaluation and collection process, bad debt expenses have not been significant; however, the Company is not able to predict changes in the financial stability of its customers. Any material change in the financial status of any one or a particular group of customers may cause the Company to adjust its estimate of the recoverability of receivables and could have a material adverse effect on the Company's results of operations. Fair values of accounts receivable approximate cost due to the short period of time to collection.

Organization and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2012

Principles of Consolidation and Basis of Presentation

The consolidated financial statements include the accounts of Level 3 Communications, Inc. and subsidiaries in which it has a controlling interest. Prior to the disposition of the coal mining business during the fourth quarter of 2011, the Company's 50% owned mining joint ventures were consolidated on a pro rata basis. All significant intercompany accounts and transactions have been eliminated. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP").

As part of its consolidation policy, the Company considers its controlled subsidiaries, investments in businesses in which the Company is not the primary beneficiary or does not have effective control but has the ability to significantly influence operating and financial policies, and variable interests resulting from economic arrangements that give the Company rights to economic risks or rewards of a legal entity. The Company does not have variable interests in a variable interest entity where it is required to consolidate the entity as the primary beneficiary or where it has concluded it is not the primary beneficiary.

Foreign Currency Translation

Local currencies of foreign subsidiaries are the functional currencies for financial reporting purposes except for certain foreign subsidiaries in Latin America. For operations outside the U.S. that have functional currencies other than the U.S. dollar, assets and liabilities are translated to U.S. dollars at period-end exchange rates, and revenue, expenses and cash flows are translated using average exchange rates prevailing during the year. Gains or losses resulting from currency translation are recorded as a component of accumulated other comprehensive loss in stockholders' equity (deficit) and in the consolidated statements of comprehensive loss. A significant portion of the Company's foreign subsidiaries have either the British Pound or the Euro as the functional currency, both of which experienced significant fluctuations against the U.S. dollar during 2012, 2011 and 2010. As a result of the Amalgamation during the fourth quarter of 2011, the Company also is exposed to fluctuations in the Brazilian Real. The Company has experienced significant foreign currency translation adjustments that are recognized as a component of accumulated other comprehensive income (loss) in stockholders' equity (deficit) and in the consolidated statement of comprehensive loss in accordance with accounting guidance for foreign currency translation. The Company considers the majority of its investments in its foreign subsidiaries to be long-term in nature. The Company's foreign exchange transaction gains (losses), including where its investments in its foreign subsidiaries are not considered to be long-term in nature, are included within other income (expense) on the consolidated statement of operations.

Reclassifications

Certain immaterial reclassifications have been made to prior years to conform to the current period's presentation.

Use of Estimates

The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reported period. The accounting estimates that require management's judgments include revenue recognition, revenue reserves, cost of revenue for communications services, the determination of the useful lives of long-lived assets, the valuation and recognition of stock-based compensation expense, the valuation of long-lived assets, goodwill and acquired indefinite-lived intangible assets, derivative financial instruments, the valuation of asset retirement obligations, the allowance for doubtful accounts, the recognition of the fair value of assets acquired and liabilities assumed in business combinations, accruals for estimated tax and legal liabilities, valuation allowance for deferred tax assets, and valuation of other assets and liabilities measured at fair value. Actual results could differ from these estimates under different assumptions or conditions and such differences could be material.

Revenue and Cost of Revenue for Communications Services

Revenue for communications services is recognized monthly as the services are provided based on contractual amounts expected to be collected. Management establishes appropriate revenue reserves at the time services are rendered based on an analysis of historical credit activity to address, where significant, situations in which collection is not reasonably assured as a result of credit risk, potential billing disputes or other reasons. Actual results may differ from these estimates under different assumptions or conditions and such differences could be material.

Intercarrier compensation revenue is recognized when an interconnection agreement is in place with another carrier, or if an agreement has expired, when the parties have agreed to continue operating under the previous agreement until a new agreement is negotiated and executed, or at rates mandated by the FCC.

For certain sale and long-term indefeasible right of use, or IRU, contracts involving private line, wavelengths and dark fiber services, the Company may receive up-front payments for services to be delivered for a period of up to 25 years. In these situations, the Company defers the revenue and amortizes it on a straight-line basis to earnings over the term of the contract.

Termination revenue is recognized when a customer discontinues service prior to the end of the contract period for which Level 3 had previously received consideration and for which revenue recognition was deferred. Termination revenue also is recognized when customers are required to make termination penalty payments to Level 3 to settle contractually committed purchase amounts that the customer no longer expects to meet or when a customer and Level 3 renegotiate a contract under which Level 3 is no longer obligated to provide services for consideration previously received and for which revenue recognition has been deferred.

The Company is obligated under dark fiber IRUs and other capacity agreements to maintain its network in efficient working order and in accordance with industry standards. Customers are obligated for the term of the agreement to pay for their allocable share of the costs for operating and maintaining the network. The Company recognizes this revenue monthly as services are provided.

Level 3's customer contracts require the Company to meet certain service level commitments. If Level 3 does not meet the required service levels, it may be obligated to provide credits, usually in the form of free service, for a short period of time. The credits are a reduction to revenue and, to date, have not been material.

Cost of revenue for the communications business includes leased capacity, right-of-way costs, access charges, satellite transponder lease costs and other third party costs directly attributable to the network, but excludes depreciation and amortization and related impairment expenses.

The Company recognizes the cost of network services as they are incurred in accordance with contractual requirements. The Company disputes incorrect billings from its suppliers of network services. The most prevalent types of disputes include disputes for circuits that are not disconnected by the supplier on a timely basis and usage bills with incorrect or inadequate information. Depending on the type and complexity of the issues involved, it may and often does take several quarters to resolve the disputes. The Company establishes appropriate cost of revenue reserves for disputed supplier billings based on an analysis of historical experience in resolving disputes with its suppliers.

In determining the amount of the cost of network service expenses and related accrued liabilities to reflect in its financial statements, the Company considers the adequacy of documentation of disconnect notices, compliance with prevailing contractual requirements for submitting these disconnect notices and disputes to the provider of the network services, and compliance with its interconnection agreements with these carriers. Judgment is required in estimating the ultimate outcome of the dispute resolution process, as well as any other amounts that may be incurred to conclude the negotiations or settle any litigation. Actual results may differ from these estimates under different assumptions or conditions and such differences could be material.

Coal Mining

Prior to the sale of its coal mining business in November 2011, the Company sold coal primarily through long-term contracts with public utilities. The long-term contracts for the delivery of coal established the price, volume, and quality requirements of the coal to be delivered. Revenue under these and other contracts was generally recognized when coal was shipped to the customer.

USF and Gross Receipts Taxes

The revenue recognition standards include guidance relating to any tax assessed by a governmental authority that is directly imposed on a revenue-producing transaction between a seller and a customer and may include, but is not limited to, gross receipts taxes and certain state regulatory fees. The Company records Universal Service Fund ("USF") contributions where the Company is the primary obligor for the taxes assessed in each jurisdiction where it does business on a gross basis in its consolidated statements of operations, but generally records gross receipts taxes and certain state regulatory fees billed to its customers on a net basis in its consolidated statements of operations. Communications revenue and cost of revenue on the consolidated statements of operations includes USF contributions totaling $191 million, $107 million and $77 million for the years ended December 31, 2012, 2011 and 2010, respectively.

Advertising Costs

The Company expenses the cost of advertising as incurred. Advertising expense is included as a component of selling, general and administrative expenses in the accompanying consolidated statements of operations. Advertising expense was $20 million, $15 million and $8 million for the years ended December 31, 2012, 2011 and 2010, respectively.

Share-Based Compensation

Stock-Based Compensation

The Company recognizes the estimated fair value of stock based compensation costs, net of an estimated forfeiture rate, over the requisite service period of the award, which is generally the vesting term or term for restrictions on transfer that lapse, as the case may be. The Company funded a portion of its 2012, 2011 and 2010 discretionary bonus in stock awards that were vested upon issuance. The Company estimates forfeiture rates based on its historical experience for the type of award.

Income Taxes

The Company recognizes deferred tax assets and liabilities for its domestic and foreign operations, for the expected tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts using enacted tax rates in effect for the year the differences are expected to reverse. The Company records a valuation allowance to reduce the deferred tax assets to the amount that is more likely than not to be realized. The Company recognizes interest and penalty expense associated with uncertain tax positions as a component of income tax expense in the consolidated statements of operations.

Cash and Cash Equivalents

The Company classifies investments as cash equivalents if they are readily convertible to cash and have original maturities of three months or less at the time of acquisition. Cash and cash equivalents consist primarily of highly liquid investments in government and government agency securities and money market funds issued or managed by financial institutions in the U.S., Europe and Latin America and commercial paper depending on liquidity requirements. As of December 31, 2012 and 2011, the carrying value of cash and cash equivalents approximates fair value due to the short period of time to maturity.

Restricted Cash and Securities

Restricted cash and securities consists primarily of cash and investments that serve to collateralize outstanding letters of credit and certain performance and operating obligations of the Company. Restricted cash and securities are recorded as current or non-current assets in the consolidated balance sheets depending on the duration of the restriction and the purpose for which the restriction exists. Restricted cash and securities are stated at cost which approximates fair value as of December 31, 2012 and 2011.

Derivatives Financial Instruments

Derivative Financial Instruments

All derivative instruments are measured at fair value and recognized as either assets or liabilities on the Company's consolidated balance sheets. The Company's derivative instruments are valued primarily using models based on readily observable market parameters for all substantial terms of the Company's derivative contracts and thus are classified as Level 2 of the GAAP fair value hierarchy (see Note 10 - Fair Value of Financial Instruments). The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation.

For derivative instruments designated as cash flow hedges, the effective portion of the derivative's gain (loss) is initially reported as a component of Accumulated Other Comprehensive Income (Loss) ("AOCI") and is subsequently recognized in earnings in the period the hedged transaction affects earnings or when they are no longer effective. Gains (losses) resulting from hedge ineffectiveness and those resulting from changes in fair values on derivatives not designated as hedging instruments are recognized in other income (expense) in the consolidated statements of operations (see Note 11 - Derivative Financial Instruments).

Allowance for Doubtful Accounts

Allowance for Doubtful AccountsTrade accounts receivable are recorded at the invoiced amount and can bear interest. The Company establishes an allowance for doubtful accounts for accounts receivable amounts that may not be collectible. The Company determines the allowance for doubtful accounts based on the aging of its accounts receivable balances and an analysis of its historical experience of bad debt write-offs. The Company reviews its allowance for doubtful accounts quarterly. Accounts receivable balances are written off against the allowance for doubtful accounts after all means of collection have been exhausted and the potential for recovery is considered remote. The Company recognized bad debt expense, net of recoveries, of approximately $15 million in 2012, $6 million in 2011 and $16 million in 2010.

Property, Plant and Equipment

In connection with the acquisition of Global Crossing in 2011, the Company evaluated the estimated useful lives of its fixed assets and determined that the period it expected to use conduit, fiber, and certain transmission equipment was longer than the remaining originally estimated useful lives. The Company revised its estimated useful lives of conduit from its historical estimate of 25 years to a revised estimate of 50 years; of fiber from its historical estimate of 12 years to a revised estimate of 25 years ; and of certain transmission equipment from its historical estimate of 7 years to its revised estimate of 15 years. In determining the change in estimated useful lives, the Company, with input from its engineering team, considered its historical usage patterns and retirements, estimates of technological obsolescence, and expected usage and maintenance.

Property, Plant and Equipment

Property, plant and equipment are recorded at cost.

Leasehold improvements are depreciated over the shorter of their estimated useful lives or lease terms that are reasonably assured.

The Company capitalizes costs directly associated with expansions and improvements of the Company's communications network and customer installations, including employee-related costs, and generally capitalizes costs associated with network construction and provisioning of services. The Company amortizes such costs over an estimated useful life of 3 to 7 years.

In addition, the Company continues to develop business support systems required for its business. The external direct costs of software, materials and services, and payroll and payroll-related expenses for employees directly associated with business support systems projects are capitalized. Upon the completion of a project, the total cost of the business support system is amortized over an estimated useful life of 3 years.

Asset Retirement Obligations

The Company recognizes a liability for the estimated fair value of legal obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or the normal operation of a long-lived asset in the period incurred. The fair value of the obligation is also capitalized as property, plant and equipment and then amortized over the estimated remaining useful life of the associated asset. Increases to the asset retirement obligation liability due to the passage of time are recognized as accretion expense and included within selling, general and administrative expenses and within income (loss) from discontinued operations for reclamation associated with the coal mining business on the Company's consolidated statements of operations prior to the sale of the coal mining business in November 2011. Changes in the liability due to revisions to the amount or timing of future cash flows are recognized by increasing or decreasing the liability with the offset adjusting the carrying amount of the related long-lived asset. To the extent that the downward revisions exceed the carrying amount of the related long-lived asset initially recorded when the asset retirement obligation liability was established, the Company records the remaining adjustment as a reduction to depreciation expense, to the extent of historical depreciation of the related long-lived asset, and then to selling, general and administrative expense.

Goodwill and Acquired Indefinite-Lived Intangible Assets

Accounting guidance prohibits the amortization of goodwill and purchased intangible assets with indefinite useful lives. The Company reviews goodwill and purchased intangible assets with indefinite lives for impairment annually at the end of the fourth quarter and whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable.

The Company's goodwill impairment review process considers the fair value of each reporting unit relative to its carrying value. If the fair value of the reporting unit exceeds its carrying value, goodwill is not impaired and no further testing is performed. If the carrying value of the reporting unit exceeds its fair value, then a second step must be performed, and the implied fair value of the reporting unit's goodwill must be determined and compared to the carrying value of the reporting unit's goodwill. If the carrying value of a reporting unit's goodwill exceeds its implied fair value, then an impairment loss equal to the difference will be recorded. Beginning with the 2011 assessment in accordance with updated accounting guidance, prior to performing the two step evaluation, an assessment of qualitative factors may be performed to determine whether it is more likely than not that the fair value of a reporting unit exceeds the carrying value. If it is determined that it is unlikely that the carrying value exceeds the fair value, the Company is not required to complete the two step goodwill impairment evaluation.

In 2012, the Company's reporting units consist of its three regional operating units in: North America; Europe, the Middle East and Africa ("EMEA"); and Latin America. In 2011, the Company's reporting units were consistent with its reportable segments of Level 3 and Global Crossing, representing the stand-alone operations of each legacy business. In 2010, the Company's reporting units were consistent with its reportable segments of communications and coal mining.

In 2012 and 2011, the Company conducted its assessment of qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit exceeds the carrying value. During 2010, the Company considered the use of multiple valuation techniques in accordance with GAAP Fair Value Measurements and Disclosures guidance to estimate the fair value of its reporting units and had consistently applied a market approach as part of its impairment assessment process. Under the market approach, the Company estimated the fair value using an in-exchange valuation premise based upon the market capitalization of Level 3 using quoted market prices, added an estimated control premium, and then assigned that fair market value to the reporting units.

The Company's indefinite-lived intangibles assets impairment review process compares the fair value of the indefinite-lived intangible assets to their respective carrying values. If the fair value of the indefinite-lived intangible assets exceeds their carrying values, then the indefinite-lived intangible assets are not impaired. If the carrying value of the indefinite-lived intangible assets exceeds their fair value, then an impairment loss equal to the difference will be recorded. In accordance with recently issued accounting guidance, an entity may assess qualitative factors to determine whether it is more likely than not that the fair value exceeds the carrying value prior to performing the two step evaluation. If it is determined that it is unlikely the carrying value exceeds the fair value, then the entity is no longer required to complete the two step indefinite-lived intangible assets impairment evaluation.

In 2012, the Company conducted its indefinite-lived intangible assets impairment analysis using the qualitative assessment to determine whether it is more likely than not that the fair value of its indefinite-lived intangible assets exceeds the carrying value. In 2011 and 2010, the Company estimated the fair value of its indefinite-lived intangible assets primarily utilizing an income approach. The Company recognizes an impairment loss when the estimated fair value of the indefinite-lived intangible assets is less than the carrying value.

The Company conducted its goodwill and acquired indefinite-lived intangible assets impairment analysis at the end of 2012, 2011 and 2010 and in each case concluded that its goodwill was not impaired in any of those periods. The Company conducted its indefinite-lived intangible asset impairment analysis at the end of 2012 and 2010 and concluded that there was no impairment. During 2011, the Company determined that the carrying value of certain wireless spectrum licenses that it acquired in a prior acquisition was impaired and the Company recognized a $20 million charge in the fourth quarter that was recognized in Other Expense. The Company concluded that its remaining indefinite-lived intangible assets were not impaired as of December 31, 2011.

Long-Lived Assets Including Finte-Lived Purchased Intangible Assets

Long-Lived Assets Including Finite-Lived Purchased Intangible Assets

The Company amortizes acquired intangible assets with finite lives using the straight-line method over the estimated economic lives of the assets, ranging from 4 to 12 years.

Impairment of Finite Lived Intangible Assets and Property Plant and Equipment

The Company evaluates long-lived assets, such as property, plant and equipment and acquired intangible assets with finite lives, for impairment whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable. The Company assesses the recoverability of the assets based on the undiscounted future cash flows the asset groups are expected to generate and recognizes an impairment loss when estimated undiscounted future cash flows expected to result from the use of the assets plus net proceeds expected from disposition of the assets, if any, are less than the carrying value of the assets. If an asset is deemed to be impaired, the amount of the impairment loss is the excess of the asset's carrying value over its estimated fair value.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash equivalents, accounts receivable, restricted cash and securities and derivatives. The Company maintains its cash equivalents, restricted cash and securities and derivatives with various financial institutions. These financial institutions are primarily located in the United States, Europe and Latin America and the Company's policy is to limit exposure with any one institution. As part of its cash and risk management processes, the Company performs periodic evaluations of the relative credit standing of the financial institutions. The Company also has established guidelines relative to financial instrument credit ratings, diversification and maturities that seek to maintain safety and liquidity. The Company's investment strategy generally results in lower yields on investments but reduces the risk to principal in the short term prior to these funds being used in the Company's business. The Company has not experienced any material losses on financial instruments held at financial institutions. From time to time, the Company utilizes interest rate swap contracts to protect against the effects of interest rate fluctuations. Such contracts involve the risk of non-performance by the counterparty, which could result in a material loss.

The Company provides communications services to a wide range of wholesale and enterprise customers, ranging from well capitalized national carriers to small early stage companies primarily in the United States, Europe, and Latin America. Credit risk with respect to accounts receivable is generally diversified due to the large number of entities comprising Level 3's customer base and their dispersion across many different industries and geographical regions. The Company performs ongoing credit evaluations of its customers' financial condition and generally requires no collateral from its customers, although letters of credit and deposits are required in certain limited circumstances. The Company has from time to time entered into agreements with value-added resellers and other channel partners to reach consumer and enterprise markets for voice services. The Company has policies and procedures in place to evaluate the financial condition of these resellers prior to initiating service to the final customer. The Company maintains an allowance for doubtful accounts based upon the expected collectability of accounts receivable. Due to the Company's credit evaluation and collection process, bad debt expenses have not been significant; however, the Company is not able to predict changes in the financial stability of its customers. Any material change in the financial status of any one or a particular group of customers may cause the Company to adjust its estimate of the recoverability of receivables and could have a material adverse effect on the Company's results of operations. Fair values of accounts receivable approximate cost due to the short period of time to collection.