The Company and Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2015
Accounting Policies [Abstract]
The Company and Summary of Significant Accounting Policies	The Company and Summary of Significant Accounting Policies The Company eBay Inc. is a global commerce leader, including our Marketplace, StubHub and Classifieds platforms. Our Marketplace platforms include our online marketplace located at www.ebay.com, its localized counterparts and the eBay mobile apps. Our StubHub platforms include our online ticket platform located at www.stubhub.com and the StubHub mobile apps. Our Classifieds platforms include a collection of brands such as Mobile.de, Kijiji, Gumtree, Marktplaats, eBay Classifieds and others. On July 17, 2015, we completed the distribution of 100% of the outstanding common stock of PayPal Holdings, Inc. ("PayPal") to our stockholders (the "Distribution"), pursuant to which PayPal became an independent company. Beginning in the third quarter of 2015, PayPal's financial results for periods prior to the Distribution have been reflected in our consolidated statement of income, retrospectively, as discontinued operations. Additionally, the related assets and liabilities associated with the discontinued operations in the prior year consolidated balance sheet are classified as discontinued operations. Pursuant to the terms of the separation and distribution agreement entered into between us and PayPal on June 26, 2015, upon Distribution, assets related to the PayPal business were transferred to, and liabilities related to the PayPal business were retained or assumed by, PayPal. See "Note 4 - Discontinued Operations" for additional information. During the second quarter of 2015, our Board of Directors ("Board") approved a plan to sell the businesses underlying our former Enterprise segment ("Enterprise"). As a result, the Enterprise financial results were reflected in our consolidated statement of income, retrospectively, as discontinued operations beginning in the second quarter of 2015. On July 16, 2015, we signed a definitive agreement to sell Enterprise and on November 2, 2015, the sale closed. As a result, the related assets and liabilities associated with the discontinued operations in the prior year consolidated balance sheet are classified as discontinued operations. See "Note 4 - Discontinued Operations" for additional information. When we refer to “we,” “our,” “us” or “eBay” in this document, we mean the current Delaware corporation (eBay Inc.) and its California predecessor, as well as all of our consolidated subsidiaries, unless otherwise expressly stated or the context otherwise requires. Use of estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles ("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 consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, we evaluate our estimates, including those related to provisions for transaction losses, legal contingencies, income taxes, revenue recognition, stock-based compensation, goodwill and the recoverability of intangible assets. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. Actual results could differ from those estimates. Principles of consolidation and basis of presentation The accompanying financial statements are consolidated and include the financial statements of eBay Inc., our wholly and majority-owned subsidiaries and variable interest entities (“VIE”) where we are the primary beneficiary. All intercompany balances and transactions have been eliminated in consolidation. Minority interests are recorded as a noncontrolling interest. A qualitative approach is applied to assess the consolidation requirement for VIEs. Investments in entities where we hold at least a 20% ownership interest and have the ability to exercise significant influence, but not control, over the investee are accounted for using the equity method of accounting. For such investments, our share of the investees' results of operations is included in interest and other, net and our investment balance is included in long-term investments. Investments in entities where we hold less than a 20% ownership interest are generally accounted for using the cost method of accounting, and our share of the investees' results of operations is included in our consolidated statement of income to the extent dividends are received. We have evaluated all subsequent events through the date the financial statements were issued. Revenue recognition We generate net transaction revenues primarily from final value fees and listing fees paid by sellers. Final value fee revenues are recognized at the time that the transaction is successfully closed, while listing fee revenues are recognized ratably over the estimated period of the listing. An auction transaction is considered successfully closed when at least one buyer has bid above the seller's specified minimum price or reserve price, whichever is higher, at the end of the transaction term. Our marketing services revenues are derived principally from the sale of advertisements, revenue sharing arrangements, classifieds fees, marketing service fees and lead referral fees. Our advertising revenues are derived principally from the sale of online advertisements. The duration of our advertising contracts has ranged from one week to five years, but is generally one week to one year. Advertising revenues on contracts are recognized as “impressions” (i.e., the number of times that an advertisement appears in pages viewed by users of our platforms) are delivered, or as “clicks” (which are generated each time users on our platforms click through our advertisements to an advertiser's designated website) are provided to advertisers. For contracts with minimum monthly or quarterly advertising commitments where the fee and commitments are fixed throughout the term, we recognize revenue ratably over the term of the agreement. We also may enter into arrangements to purchase services from certain customers and if the service is not considered an identifiable benefit that is separable from the customer's purchase of our services or for which we cannot reasonably estimate fair value, the fees paid to the customer is recorded as a reduction in revenue. Some of our advertising contracts consist of multiple elements which generally include a blend of various impressions and clicks as well as other marketing deliverables. Where neither vendor-specific objective evidence nor third-party evidence of selling price exists, we use management's best estimate of selling price (BESP) to allocate arrangement consideration on a relative basis to each element. BESP is generally based on the selling prices of the various elements when they are sold to customers of a similar nature and geography on a stand-alone basis or estimated stand-alone pricing when the element has not previously been sold on a stand-alone basis. These estimates are generally based on pricing strategies, market factors and strategic objectives. Revenues related to revenue sharing arrangements are recognized based on revenue reports received from our partners, provided that collectability is reasonably assured. Revenues related to fees for listing items on our Classifieds platforms are recognized over the estimated period of the classified listing. Lead referral fee revenue is generated from lead referral fees based on the number of times users click through to a merchant's website from our platforms. Lead referral fees are recognized in the period in which a user clicks through to the merchant's website. Our other revenues are derived principally from contractual arrangements with third parties that provide services to our users. Revenues from contractual arrangements with third parties are recognized as the contracted services are delivered to end users. To drive traffic to our platforms, we provide incentives to our users in the form of coupons and buyer and seller rewards. These incentives are generally treated as reductions in revenue. Internal use software and platform development costs Direct costs incurred to develop software for internal use and platform development costs are capitalized and amortized over an estimated useful life of one to five years. During the years ended December 31, 2015 and 2014, we capitalized costs, primarily related to labor and stock-based compensation, of $136 million and $144 million, respectively. Amortization of previously capitalized amounts was $110 million, $115 million and $103 million for 2015, 2014 and 2013, respectively. Costs related to the design or maintenance of internal use software and platform development are expensed as incurred. Advertising expense We expense the costs of producing advertisements at the time production occurs and expense the cost of communicating advertisements in the period during which the advertising space or airtime is used, in each case as sales and marketing expense. Internet advertising expenses are recognized based on the terms of the individual agreements, which are generally over the greater of the ratio of the number of impressions delivered over the total number of contracted impressions, on a pay-per-click basis, or on a straight-line basis over the term of the contract. Advertising expense totaled $1.0 billion, $1.0 billion and $844 million for the years ended December 31, 2015, 2014 and 2013, respectively. Stock-based compensation We have equity incentive plans under which we grant equity awards, including stock options, restricted stock units, performance-based restricted stock units, and performance share units, to our directors, officers and employees. We primarily issue restricted stock units. We determine compensation expense associated with restricted stock units based on the fair value of our common stock on the date of grant. We determine compensation expense associated with stock options based on the estimated grant date fair value method using the Black-Scholes valuation model. We generally recognize compensation expense using a straight-line amortization method over the respective vesting period for awards that are ultimately expected to vest. Accordingly, stock-based compensation expense for 2015, 2014 and 2013 has been reduced for estimated forfeitures. When estimating forfeitures, we consider voluntary termination behaviors as well as trends of actual option forfeitures. We recognize a benefit from stock-based compensation in equity to the extent that an incremental tax benefit is realized by following the ordering provisions of the tax law. In addition, we account for the indirect effects of stock-based compensation on the research tax credit and the foreign tax credit through our consolidated statement of income. Provision for transaction losses Provision for transaction losses consists primarily of losses resulting from our customer protection programs, fraud and bad debt expense associated with our accounts receivable balance. Provisions for these items represent our estimate of actual losses based on our historical experience and many other factors including changes to our customer protection programs, the impact of regulatory changes as well as economic conditions. Income taxes We account for income taxes using an asset and liability approach, which requires the recognition of taxes payable or refundable for the current year and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in our financial statements or tax returns. The measurement of current and deferred tax assets and liabilities is based on provisions of enacted tax laws; the effects of future changes in tax laws or rates are not anticipated. If necessary, the measurement of deferred tax assets is reduced by the amount of any tax benefits that are not expected to be realized based on available evidence. We report a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. We recognize interest and penalties, if any, related to unrecognized tax benefits in income tax expense. Cash and cash equivalents Cash and cash equivalents are short-term, highly liquid investments with original maturities of three months or less when purchased and are mainly comprised of bank deposits, certificates of deposit and commercial paper. Allowance for doubtful accounts and authorized credits We record our allowance for doubtful accounts based upon our assessment of various factors. We consider historical experience, the age of the accounts receivable balances, current economic conditions and other factors that may affect our customers' ability to pay. The allowance for doubtful accounts and authorized credits was $84 million and $86 million at December 31, 2015 and 2014, respectively. Investments Short-term investments, which may include marketable equity securities, time deposits, certificates of deposit, government bonds and corporate debt securities with original maturities of greater than three months but less than one year when purchased, are classified as available-for-sale and are reported at fair value using the specific identification method. Unrealized gains and losses are excluded from earnings and reported as a component of other comprehensive income (loss), net of related estimated tax provisions or benefits. Long-term investments may include marketable government bonds and corporate debt securities, time deposits, certificates of deposit and cost and equity method investments. Debt securities are classified as available-for-sale and are reported at fair value using the specific identification method. Unrealized gains and losses on our available-for-sale investments are excluded from earnings and reported as a component of other comprehensive income (loss), net of related estimated tax provisions or benefits. Certain time deposits are classified as held to maturity and recorded at amortized cost. Our equity method investments are primarily investments in privately held companies. Our consolidated results of operations include, as a component of interest and other, net, our share of the net income or loss of the equity method investments. Our share of investees' results of operations is not significant for any period presented. Our cost method investments consist of investments in privately held companies and are recorded at cost. Amounts received from our cost method investees were not material to any period presented. We assess whether an other-than-temporary impairment loss on our investments has occurred due to declines in fair value or other market conditions. With respect to our debt securities, this assessment takes into account the severity and duration of the decline in value, our intent to sell the security, whether it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis, and whether we expect to recover the entire amortized cost basis of the security (that is, whether a credit loss exists). Property and equipment Property and equipment are stated at historical cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally, one to three years for computer equipment and software, up to thirty years for buildings and building improvements, the shorter of five years or the term of the lease for leasehold improvements and three years for furniture, fixtures and vehicles. Goodwill and intangible assets Goodwill is tested for impairment at a minimum on an annual basis. Goodwill is tested for impairment at the reporting unit level. A qualitative assessment can be performed to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying value. If the reporting unit does not pass the qualitative assessment, then the reporting unit's carrying value is compared to its fair value. The fair values of the reporting units are estimated using income and market approaches. Goodwill is considered impaired if the carrying value of the reporting unit exceeds its fair value. The discounted cash flow method, a form of the income approach, uses expected future operating results and a market participant discount rate. The market approach uses comparable company prices and other relevant information generated by market transactions (either publicly traded entities or merger and acquisitions) to develop pricing metrics to be applied to historical and expected future operating results of our reporting units. Failure to achieve these expected results, changes in the discount rate or market pricing metrics may cause a future impairment of goodwill at the reporting unit. We conducted our annual impairment test of goodwill as of August 31, 2015 and 2014. Additionally, we evaluated impairment based on the significant activities regarding the Distribution and Enterprise divestiture during the year. See “Note 4 - Discontinued Operations” for further detail. As a result of this test, we determined that no further adjustment to the carrying value of goodwill for any reporting units was required. Intangible assets consist of purchased customer lists and user base, marketing related, developed technologies and other intangible assets, including patents and contractual agreements. Intangible assets are amortized over the period of estimated benefit using the straight-line method and estimated useful lives ranging from one to eight years. No significant residual value is estimated for intangible assets. Impairment of long-lived assets We evaluate long-lived assets (including intangible assets) for impairment whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset may not be recoverable. An asset is considered impaired if its carrying amount exceeds the undiscounted future net cash flow the asset is expected to generate. In 2015, 2014 and 2013, no impairment was noted. Foreign currency Most of our foreign subsidiaries use the local currency of their respective countries as their functional currency. Assets and liabilities are translated at exchange rates prevailing at the balance sheet dates. Revenues, costs and expenses are translated into U.S. dollars using daily exchange rates if the transaction is recorded in our accounting systems on a daily basis, and otherwise using average exchange rates for the period. Gains and losses resulting from the translation of our consolidated balance sheet are recorded as a component of accumulated other comprehensive income. Gains and losses from foreign currency transactions are recognized as interest and other, net. Derivative instruments We use derivative financial instruments, primarily forwards and swaps, to hedge certain foreign currency and interest rate exposures. We may also use other derivative instruments not designated as hedges, such as forwards used to hedge foreign currency balance sheet exposures. We do not use derivative financial instruments for trading purposes. See “Note 9 - Derivative Instruments” for a full description of our derivative instrument activities and related accounting policies. Concentration of credit risk Our cash, cash equivalents, accounts receivable and derivative instruments are potentially subject to concentration of credit risk. Cash and cash equivalents are placed with financial institutions that management believes are of high credit quality. Our accounts receivable are derived from revenue earned from customers. In each of the years ended December 31, 2015, 2014 and 2013, no customer accounted for more than 10% of net revenues. Our derivative instruments expose us to credit risk to the extent that our counterparties may be unable to meet the terms of the agreements. Recent Accounting Pronouncements In 2014, the FASB issued new guidance related to reporting discontinued operations. This new standard raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. The new standard is now effective. The standard impacted the presentation of Enterprise during the second quarter of 2015 and PayPal during the third quarter of 2015 related to the financial statement presentation of assets held for sale and discontinued operations and required additional disclosures as presented in "Note 4 - Discontinued Operations." In 2014, the FASB issued new accounting guidance related to revenue recognition. This new standard will replace all current GAAP guidance on this topic and eliminate all industry-specific guidance. The new revenue recognition guidance provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. This guidance can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. In 2015, the FASB issued guidance to defer the effective date to fiscal years beginning after December 15, 2017 with early adoption for fiscal years beginning December 15, 2016. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements. In 2015, the FASB issued new guidance related to consolidations. The new standard amends the guidelines for determining whether certain legal entities should be consolidated and reduces the number of consolidation models. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. We are evaluating the impact, if any, of adopting this new accounting guidance on our consolidated financial statements. In 2015, the FASB issued new guidance related to presentation of debt issuance costs. The new standard requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. The adoption of this standard is not expected to have a material impact on our consolidated financial statements. In 2015, the FASB issued new guidance related to accounting for fees paid in a cloud computing arrangement. The new standard provides guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. We are evaluating the impact, if any, of adopting this new accounting guidance on our consolidated financial statements. In 2015, the FASB issued new guidance related to business combinations. The new guidance requires that adjustments made to provisional amounts recognized in a business combination be recorded in the period such adjustments are determined, rather than retrospectively adjusting previously reported amounts. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. We are evaluating the impact, if any, of adopting this new accounting guidance on our consolidated financial statements. In 2015, the FASB issued new guidance related to balance sheet classification of deferred taxes. The new guidance requires that deferred tax assets and liabilities be classified as noncurrent in a classified statement of financial position. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. Early adoption is permitted. We early adopted this guidance on a prospective basis as of December 31, 2015. See "Note 17 - Income Taxes" for additional information. In 2016, the FASB issued new guidance related accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the FASB clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements.

The Company and Summary of Significant Accounting Policies

The Company

eBay Inc. is a global commerce leader, including our Marketplace, StubHub and Classifieds platforms. Our Marketplace platforms include our online marketplace located at www.ebay.com, its localized counterparts and the eBay mobile apps. Our StubHub platforms include our online ticket platform located at www.stubhub.com and the StubHub mobile apps. Our Classifieds platforms include a collection of brands such as Mobile.de, Kijiji, Gumtree, Marktplaats, eBay Classifieds and others.

On July 17, 2015, we completed the distribution of 100% of the outstanding common stock of PayPal Holdings, Inc. ("PayPal") to our stockholders (the "Distribution"), pursuant to which PayPal became an independent company. Beginning in the third quarter of 2015, PayPal's financial results for periods prior to the Distribution have been reflected in our consolidated statement of income, retrospectively, as discontinued operations. Additionally, the related assets and liabilities associated with the discontinued operations in the prior year consolidated balance sheet are classified as discontinued operations. Pursuant to the terms of the separation and distribution agreement entered into between us and PayPal on June 26, 2015, upon Distribution, assets related to the PayPal business were transferred to, and liabilities related to the PayPal business were retained or assumed by, PayPal. See "Note 4 - Discontinued Operations" for additional information.

During the second quarter of 2015, our Board of Directors ("Board") approved a plan to sell the businesses underlying our former Enterprise segment ("Enterprise"). As a result, the Enterprise financial results were reflected in our consolidated statement of income, retrospectively, as discontinued operations beginning in the second quarter of 2015. On July 16, 2015, we signed a definitive agreement to sell Enterprise and on November 2, 2015, the sale closed. As a result, the related assets and liabilities associated with the discontinued operations in the prior year consolidated balance sheet are classified as discontinued operations. See "Note 4 - Discontinued Operations" for additional information.

When we refer to “we,” “our,” “us” or “eBay” in this document, we mean the current Delaware corporation (eBay Inc.) and its California predecessor, as well as all of our consolidated subsidiaries, unless otherwise expressly stated or the context otherwise requires.

Use of estimates

The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles ("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 consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, we evaluate our estimates, including those related to provisions for transaction losses, legal contingencies, income taxes, revenue recognition, stock-based compensation, goodwill and the recoverability of intangible assets. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. Actual results could differ from those estimates.

Principles of consolidation and basis of presentation

The accompanying financial statements are consolidated and include the financial statements of eBay Inc., our wholly and majority-owned subsidiaries and variable interest entities (“VIE”) where we are the primary beneficiary. All intercompany balances and transactions have been eliminated in consolidation. Minority interests are recorded as a noncontrolling interest. A qualitative approach is applied to assess the consolidation requirement for VIEs. Investments in entities where we hold at least a 20% ownership interest and have the ability to exercise significant influence, but not control, over the investee are accounted for using the equity method of accounting. For such investments, our share of the investees' results of operations is included in interest and other, net and our investment balance is included in long-term investments. Investments in entities where we hold less than a 20% ownership interest are generally accounted for using the cost method of accounting, and our share of the investees' results of operations is included in our consolidated statement of income to the extent dividends are received.

We have evaluated all subsequent events through the date the financial statements were issued.

Revenue recognition

We generate net transaction revenues primarily from final value fees and listing fees paid by sellers. Final value fee revenues are recognized at the time that the transaction is successfully closed, while listing fee revenues are recognized ratably over the estimated period of the listing. An auction transaction is considered successfully closed when at least one buyer has bid above the seller's specified minimum price or reserve price, whichever is higher, at the end of the transaction term.

Our marketing services revenues are derived principally from the sale of advertisements, revenue sharing arrangements, classifieds fees, marketing service fees and lead referral fees. Our advertising revenues are derived principally from the sale of online advertisements. The duration of our advertising contracts has ranged from one week to five years, but is generally one week to one year. Advertising revenues on contracts are recognized as “impressions” (i.e., the number of times that an advertisement appears in pages viewed by users of our platforms) are delivered, or as “clicks” (which are generated each time users on our platforms click through our advertisements to an advertiser's designated website) are provided to advertisers. For contracts with minimum monthly or quarterly advertising commitments where the fee and commitments are fixed throughout the term, we recognize revenue ratably over the term of the agreement. We also may enter into arrangements to purchase services from certain customers and if the service is not considered an identifiable benefit that is separable from the customer's purchase of our services or for which we cannot reasonably estimate fair value, the fees paid to the customer is recorded as a reduction in revenue. Some of our advertising contracts consist of multiple elements which generally include a blend of various impressions and clicks as well as other marketing deliverables. Where neither vendor-specific objective evidence nor third-party evidence of selling price exists, we use management's best estimate of selling price (BESP) to allocate arrangement consideration on a relative basis to each element. BESP is generally based on the selling prices of the various elements when they are sold to customers of a similar nature and geography on a stand-alone basis or estimated stand-alone pricing when the element has not previously been sold on a stand-alone basis. These estimates are generally based on pricing strategies, market factors and strategic objectives. Revenues related to revenue sharing arrangements are recognized based on revenue reports received from our partners, provided that collectability is reasonably assured. Revenues related to fees for listing items on our Classifieds platforms are recognized over the estimated period of the classified listing. Lead referral fee revenue is generated from lead referral fees based on the number of times users click through to a merchant's website from our platforms. Lead referral fees are recognized in the period in which a user clicks through to the merchant's website.

Our other revenues are derived principally from contractual arrangements with third parties that provide services to our users. Revenues from contractual arrangements with third parties are recognized as the contracted services are delivered to end users.

To drive traffic to our platforms, we provide incentives to our users in the form of coupons and buyer and seller rewards. These incentives are generally treated as reductions in revenue.

Internal use software and platform development costs

Direct costs incurred to develop software for internal use and platform development costs are capitalized and amortized over an estimated useful life of one to five years. During the years ended December 31, 2015 and 2014, we capitalized costs, primarily related to labor and stock-based compensation, of $136 million and $144 million, respectively. Amortization of previously capitalized amounts was $110 million, $115 million and $103 million for 2015, 2014 and 2013, respectively. Costs related to the design or maintenance of internal use software and platform development are expensed as incurred.

Advertising expense

We expense the costs of producing advertisements at the time production occurs and expense the cost of communicating advertisements in the period during which the advertising space or airtime is used, in each case as sales and marketing expense. Internet advertising expenses are recognized based on the terms of the individual agreements, which are generally over the greater of the ratio of the number of impressions delivered over the total number of contracted impressions, on a pay-per-click basis, or on a straight-line basis over the term of the contract. Advertising expense totaled $1.0 billion, $1.0 billion and $844 million for the years ended December 31, 2015, 2014 and 2013, respectively.

Stock-based compensation

We have equity incentive plans under which we grant equity awards, including stock options, restricted stock units, performance-based restricted stock units, and performance share units, to our directors, officers and employees. We primarily issue restricted stock units. We determine compensation expense associated with restricted stock units based on the fair value of our common stock on the date of grant. We determine compensation expense associated with stock options based on the estimated grant date fair value method using the Black-Scholes valuation model. We generally recognize compensation expense using a straight-line amortization method over the respective vesting period for awards that are ultimately expected to vest. Accordingly, stock-based compensation expense for 2015, 2014 and 2013 has been reduced for estimated forfeitures. When estimating forfeitures, we consider voluntary termination behaviors as well as trends of actual option forfeitures. We recognize a benefit from stock-based compensation in equity to the extent that an incremental tax benefit is realized by following the ordering provisions of the tax law. In addition, we account for the indirect effects of stock-based compensation on the research tax credit and the foreign tax credit through our consolidated statement of income.

Provision for transaction losses

Provision for transaction losses consists primarily of losses resulting from our customer protection programs, fraud and bad debt expense associated with our accounts receivable balance. Provisions for these items represent our estimate of actual losses based on our historical experience and many other factors including changes to our customer protection programs, the impact of regulatory changes as well as economic conditions.

Income taxes

We account for income taxes using an asset and liability approach, which requires the recognition of taxes payable or refundable for the current year and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in our financial statements or tax returns. The measurement of current and deferred tax assets and liabilities is based on provisions of enacted tax laws; the effects of future changes in tax laws or rates are not anticipated. If necessary, the measurement of deferred tax assets is reduced by the amount of any tax benefits that are not expected to be realized based on available evidence.

We report a liability for unrecognized tax benefits resulting from uncertain tax positions taken or expected to be taken in a tax return. We recognize interest and penalties, if any, related to unrecognized tax benefits in income tax expense.

Cash and cash equivalents

Cash and cash equivalents are short-term, highly liquid investments with original maturities of three months or less when purchased and are mainly comprised of bank deposits, certificates of deposit and commercial paper.

Allowance for doubtful accounts and authorized credits

We record our allowance for doubtful accounts based upon our assessment of various factors. We consider historical experience, the age of the accounts receivable balances, current economic conditions and other factors that may affect our customers' ability to pay. The allowance for doubtful accounts and authorized credits was $84 million and $86 million at December 31, 2015 and 2014, respectively.

Investments

Short-term investments, which may include marketable equity securities, time deposits, certificates of deposit, government bonds and corporate debt securities with original maturities of greater than three months but less than one year when purchased, are classified as available-for-sale and are reported at fair value using the specific identification method. Unrealized gains and losses are excluded from earnings and reported as a component of other comprehensive income (loss), net of related estimated tax provisions or benefits.

Long-term investments may include marketable government bonds and corporate debt securities, time deposits, certificates of deposit and cost and equity method investments. Debt securities are classified as available-for-sale and are reported at fair value using the specific identification method. Unrealized gains and losses on our available-for-sale investments are excluded from earnings and reported as a component of other comprehensive income (loss), net of related estimated tax provisions or benefits.

Certain time deposits are classified as held to maturity and recorded at amortized cost. Our equity method investments are primarily investments in privately held companies. Our consolidated results of operations include, as a component of interest and other, net, our share of the net income or loss of the equity method investments. Our share of investees' results of operations is not significant for any period presented. Our cost method investments consist of investments in privately held companies and are recorded at cost. Amounts received from our cost method investees were not material to any period presented.

We assess whether an other-than-temporary impairment loss on our investments has occurred due to declines in fair value or other market conditions. With respect to our debt securities, this assessment takes into account the severity and duration of the decline in value, our intent to sell the security, whether it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis, and whether we expect to recover the entire amortized cost basis of the security (that is, whether a credit loss exists).

Property and equipment

Property and equipment are stated at historical cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally, one to three years for computer equipment and software, up to thirty years for buildings and building improvements, the shorter of five years or the term of the lease for leasehold improvements and three years for furniture, fixtures and vehicles.

Goodwill and intangible assets

Goodwill is tested for impairment at a minimum on an annual basis. Goodwill is tested for impairment at the reporting unit level. A qualitative assessment can be performed to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying value. If the reporting unit does not pass the qualitative assessment, then the reporting unit's carrying value is compared to its fair value. The fair values of the reporting units are estimated using income and market approaches. Goodwill is considered impaired if the carrying value of the reporting unit exceeds its fair value. The discounted cash flow method, a form of the income approach, uses expected future operating results and a market participant discount rate. The market approach uses comparable company prices and other relevant information generated by market transactions (either publicly traded entities or merger and acquisitions) to develop pricing metrics to be applied to historical and expected future operating results of our reporting units. Failure to achieve these expected results, changes in the discount rate or market pricing metrics may cause a future impairment of goodwill at the reporting unit. We conducted our annual impairment test of goodwill as of August 31, 2015 and 2014. Additionally, we evaluated impairment based on the significant activities regarding the Distribution and Enterprise divestiture during the year. See “Note 4 - Discontinued Operations” for further detail. As a result of this test, we determined that no further adjustment to the carrying value of goodwill for any reporting units was required.

Intangible assets consist of purchased customer lists and user base, marketing related, developed technologies and other intangible assets, including patents and contractual agreements. Intangible assets are amortized over the period of estimated benefit using the straight-line method and estimated useful lives ranging from one to eight years. No significant residual value is estimated for intangible assets.

Impairment of long-lived assets

We evaluate long-lived assets (including intangible assets) for impairment whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset may not be recoverable. An asset is considered impaired if its carrying amount exceeds the undiscounted future net cash flow the asset is expected to generate. In 2015, 2014 and 2013, no impairment was noted.

Foreign currency

Most of our foreign subsidiaries use the local currency of their respective countries as their functional currency. Assets and liabilities are translated at exchange rates prevailing at the balance sheet dates. Revenues, costs and expenses are translated into U.S. dollars using daily exchange rates if the transaction is recorded in our accounting systems on a daily basis, and otherwise using average exchange rates for the period. Gains and losses resulting from the translation of our consolidated balance sheet are recorded as a component of accumulated other comprehensive income.

Gains and losses from foreign currency transactions are recognized as interest and other, net.

Derivative instruments

We use derivative financial instruments, primarily forwards and swaps, to hedge certain foreign currency and interest rate exposures. We may also use other derivative instruments not designated as hedges, such as forwards used to hedge foreign currency balance sheet exposures. We do not use derivative financial instruments for trading purposes. See “Note 9 - Derivative Instruments” for a full description of our derivative instrument activities and related accounting policies.

Concentration of credit risk

Our cash, cash equivalents, accounts receivable and derivative instruments are potentially subject to concentration of credit risk. Cash and cash equivalents are placed with financial institutions that management believes are of high credit quality. Our accounts receivable are derived from revenue earned from customers. In each of the years ended December 31, 2015, 2014 and 2013, no customer accounted for more than 10% of net revenues. Our derivative instruments expose us to credit risk to the extent that our counterparties may be unable to meet the terms of the agreements.

Recent Accounting Pronouncements

In 2014, the FASB issued new guidance related to reporting discontinued operations. This new standard raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. The new standard is now effective. The standard impacted the presentation of Enterprise during the second quarter of 2015 and PayPal during the third quarter of 2015 related to the financial statement presentation of assets held for sale and discontinued operations and required additional disclosures as presented in "Note 4 - Discontinued Operations."

In 2014, the FASB issued new accounting guidance related to revenue recognition. This new standard will replace all current GAAP guidance on this topic and eliminate all industry-specific guidance. The new revenue recognition guidance provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. This guidance can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. In 2015, the FASB issued guidance to defer the effective date to fiscal years beginning after December 15, 2017 with early adoption for fiscal years beginning December 15, 2016. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements.

In 2015, the FASB issued new guidance related to consolidations. The new standard amends the guidelines for determining whether certain legal entities should be consolidated and reduces the number of consolidation models. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. We are evaluating the impact, if any, of adopting this new accounting guidance on our consolidated financial statements.

In 2015, the FASB issued new guidance related to presentation of debt issuance costs. The new standard requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. The adoption of this standard is not expected to have a material impact on our consolidated financial statements.

In 2015, the FASB issued new guidance related to accounting for fees paid in a cloud computing arrangement. The new standard provides guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. We are evaluating the impact, if any, of adopting this new accounting guidance on our consolidated financial statements.

In 2015, the FASB issued new guidance related to business combinations. The new guidance requires that adjustments made to provisional amounts recognized in a business combination be recorded in the period such adjustments are determined, rather than retrospectively adjusting previously reported amounts. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. We are evaluating the impact, if any, of adopting this new accounting guidance on our consolidated financial statements.

In 2015, the FASB issued new guidance related to balance sheet classification of deferred taxes. The new guidance requires that deferred tax assets and liabilities be classified as noncurrent in a classified statement of financial position. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. Early adoption is permitted. We early adopted this guidance on a prospective basis as of December 31, 2015. See "Note 17 - Income Taxes" for additional information.

In 2016, the FASB issued new guidance related accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the FASB clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements.