Summary of significant accounting policies (Policies)	12 Months Ended
Dec. 31, 2013
Summary of significant accounting policies
Basis of Consolidation and Presentation	Basis of Consolidation and Presentation The accompanying consolidated financial statements include the accounts and operations of the Company. All intercompany accounts and transactions have been eliminated. The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates and assumptions. Certain reclassifications have been made to prior year amounts to conform to the current period presentation. The Company considers events or transactions that occur after the balance sheet date, but before the financial statements are issued, to provide additional evidence relative to certain estimates or to identify matters that require additional disclosures.
Results of Adjustment	Results of Adjustment During the year ended December 31, 2013, we identified through our internal processes that, in previous years, we erroneously under-accrued for certain indirect taxes for two countries in our Europe region. We performed an evaluation under SEC Staff Accounting Bulletin No. 108 and concluded the effect of this error was immaterial to prior years' financial statements as well as the full-year 2013 financial statements. As such, during the year ended December 31, 2013, we recorded an adjustment in our consolidated statements of operations which reduced “Total net revenues” by $8 million, “Interest and other investment income (expense), net” by $1 million, “Income before income tax expense” by $9 million, and “Net income” by $7 million. This adjustment reduced net revenues and income from operations before income tax expense by $8 million and $9 million, respectively, in each of our Blizzard segment, Europe region, and online subscriptions platform, as presented in Note 14 of the Notes to Consolidated Financial Statements. The adjustment increased “Accrued expenses and other liabilities” on our consolidated balance sheet by $9 million and represents a correction of an error. Operating cash flows were impacted by $9 million in 2013 when we settled the liability. The adjustment related to prior periods' net income as follows: (i) approximately $1 million for the quarter ended March 31, 2013; (ii) approximately $1 million for each quarter of 2012 (totaling approximately $4 million for the year ended December 31, 2012); (iii) approximately $2 million for the year ended December 31, 2011; and (iv) less than $1 million for the year ended December 31, 2010. Earnings per basic and diluted share were affected by less than $0.01 as a result of recording this adjustment. During the year ended December 31, 2012, we identified through our internal processes that, in previous years, we erroneously over-recognized revenues for a country in our Europe region. We performed an evaluation under SEC Staff Accounting Bulletin No. 108 and concluded the effect of this error was immaterial to prior years' financial statements as well as the full-year 2012 financial statements. As such, during the year ended December 31, 2012, we recorded an adjustment in our consolidated statements of operations which reduced “Total net revenues” by $11 million and “Net income” by $8 million. This adjustment reduced net revenues and income from operations before income tax expense by $11 million in each of our Blizzard segment, Europe region, and online subscriptions platform, as presented in Note 14 of the Notes to Consolidated Financial Statements. The adjustment increased “Deferred revenues” on our consolidated balance sheet by $11 million and represents a correction of an error. There was no impact to operating cash flows. The adjustment related to prior periods' net income as follows: (i) approximately $1 million for the quarter ended March 31, 2012; (ii) less than $1 million for each quarter of 2011 (totaling approximately $3 million for the year ended December 31, 2011); (iii) approximately $2 million for the year ended December 31, 2010; and (iv) approximately $3 million for periods prior to the year ended December 31, 2010. Earnings per basic and diluted share were affected by less than $0.01 as a result of recording this adjustment.
Cash and cash equivalents	Cash and Cash Equivalents We consider all money market funds and highly liquid investments with original maturities of three months or less at the time of purchase to be “Cash and cash equivalents.”
Investment securities	Investment Securities Investments designated as available-for-sale securities are carried at fair value, which is based on quoted market prices for such securities, if available, or is estimated on the basis of quoted market prices of financial instruments with similar characteristics. Unrealized gains and losses of the Company's available-for-sale securities are excluded from earnings and are reported as a component of “Other comprehensive income (loss).” Investments with original maturities greater than 90 days and remaining maturities of less than one year are normally classified within “Short-term investments.” In addition, investments with maturities beyond one year may be classified within “Short-term investments” if they are highly liquid in nature and represent the investment of cash that is available for current operations. The specific identification method is used to determine the cost of securities disposed of, with realized gains and losses reflected in “Interest and other investment income (expense), net” in our consolidated statements of operations. The Company's investments include auction rate securities (“ARS”). These ARS are variable rate bonds tied to short-term interest rates with long-term maturities. ARS have interest rates which reset through a modified Dutch auction at predetermined short-term intervals, typically every 7, 28, or 35 days. Interest on ARS is generally paid at the end of each auction process and is based upon the interest rate determined for the prior auction. Our investments in ARS are not material to our consolidated financial statements.
Restricted cash - compensating balances	Restricted Cash—Compensating Balances Restricted cash is included within “Short-term investments” on the consolidated balance sheets. The majority of our restricted cash relates to a standby letter of credit required by one of our inventory manufacturers so that we can qualify for certain payment terms on our inventory purchases. Under the terms of this arrangement, we are required to maintain with the issuing bank a compensating balance, restricted as to use, of not less than the sum of the available amount of the letter of credit plus the aggregate amount of any drawings under the letter of credit that have been honored thereunder, but have not yet been reimbursed.
Financial instruments	Financial Instruments The carrying amount of “Cash and cash equivalents,” “Accounts receivable,” “Accounts payable,” and “Accrued expenses” substantively approximate fair value due to the short-term nature of these accounts. Our investments in U.S. treasuries, government agency securities, and corporate bonds are carried at fair value, which is based on quoted market prices for such securities, if available, or is estimated on the basis of quoted market prices of financial instruments with similar characteristics. ARS are carried at fair value, which is estimated using an income-approach model. The Company transacts business in various foreign currencies and has significant international sales and expenses denominated in foreign currencies, subjecting us to foreign currency risk. To mitigate our foreign currency exchange rate exposure resulting from our foreign currency-denominated monetary assets, liabilities, and earnings, we periodically enter into currency derivative contracts, principally forward contracts with maturities of generally less than one year. We do not use derivatives for speculative or trading purposes and we do not designate these derivatives as hedging instruments under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 815. Accordingly, we report the fair value of these contracts within “Other current assets” or “Other current liabilities” in our consolidated balance sheets and the changes in fair value within “General and administrative expenses” and “Interest and other investment income (expense), net” in our consolidated statements of operations, depending on the nature of the contracts. The fair value of foreign currency contracts are estimated based on the prevailing exchange rates of the various hedged currencies as of the end of the period.
Other-Than-Temporary Impairments	Other-Than-Temporary Impairments The Company regularly reviews its investments to determine whether a decline in fair value below the cost basis is an other-than-temporary impairment. If the decline is determined to be other-than-temporary, the cost basis of the investment is written down to fair value. For available-for-sale fixed maturity instruments where credit-related impairments exist, other-than-temporary impairments are reported in the consolidated statements of operations and non-credit impairments are reported as a component of “Other comprehensive income (loss).”
Concentration of Credit Risk	Concentration of Credit Risk Our concentration of credit risk relates to depositors holding the Company's cash and cash equivalents and customers with significant accounts receivable balances. Our cash and cash equivalents are invested primarily in money market funds consisting of short-term, high-quality debt instruments issued by governments and governmental organizations, financial institutions and industrial companies. Our customer base includes retailers and distributors, including mass-market retailers, consumer electronics stores, discount warehouses, and game specialty stores in the U.S. and other countries worldwide. We perform ongoing credit evaluations of our customers and maintain allowances for potential credit losses. We generally do not require collateral or other security from our customers. We did not have any single customer that accounted for 10% or more of net revenues for the years ended December 31, 2013 and 2011. We had one customer for the Activision and Blizzard segments, GameStop, that accounted for approximately 10% of net revenues for the year ended December 31, 2012. We had one customer, Wal-Mart, that accounted for 24% and 20% of consolidated gross receivables at December 31, 2013 and 2012, respectively.
Software Development Costs and Intellectual Property Licenses	Software Development Costs and Intellectual Property Licenses Software development costs include payments made to independent software developers under development agreements, as well as direct costs incurred for internally developed products. We account for software development costs in accordance with ASC Subtopic 985-20, the guidance for costs of computer software to be sold, leased, or otherwise marketed. Software development costs are capitalized once technological feasibility of a product is established and such costs are determined to be recoverable. Technological feasibility of a product encompasses both technical design documentation and game design documentation, or the completed and tested product design and working model. Significant management judgments and estimates are utilized in the assessment of when technological feasibility is established. For products where proven technology exists, this may occur early in the development cycle. Technological feasibility is evaluated on a product-by-product basis. Prior to a product's release, if and when we believe capitalized costs are not recoverable, we expense the amounts as part of “Cost of sales—software royalties and amortization.” Capitalized costs for products that are cancelled or are expected to be abandoned are charged to “Product development expense” in the period of cancellation. Amounts related to software development which are not capitalized are charged immediately to “Product development expense.” Commencing upon a product's release, capitalized software development costs are amortized to “Cost of sales—software royalties and amortization” based on the ratio of current revenues to total projected revenues for the specific product, generally resulting in an amortization period of six months or less. Intellectual property license costs represent license fees paid to intellectual property rights holders for use of their trademarks, copyrights, software, technology, music or other intellectual property or proprietary rights in the development of our products. Depending upon the agreement with the rights holder, we may obtain the right to use the intellectual property in multiple products over a number of years, or alternatively, for a single product. Prior to a product's release, if and when we believe capitalized costs are not recoverable, we expense the amounts as part of “Cost of sales—intellectual property licenses.” Capitalized intellectual property costs for products that are cancelled or are expected to be abandoned are charged to “Product development expense” in the period of cancellation. Commencing upon a product's release, capitalized intellectual property license costs are amortized to “Cost of sales—intellectual property licenses” based on the ratio of current revenues for the specific product to total projected revenues for all products in which the licensed property will be utilized. As intellectual property license contracts may extend for multiple years and can be used in multiple products to be released over a period beyond one year, the amortization of capitalized intellectual property license costs relating to such contracts may extend beyond one year. We evaluate the future recoverability of capitalized software development costs and intellectual property licenses on a quarterly basis. For products that have been released in prior periods, the primary evaluation criterion is actual title performance. For products that are scheduled to be released in future periods, recoverability is evaluated based on the expected performance of the specific products to which the costs relate or in which the licensed trademark or copyright is to be used. Criteria used to evaluate expected product performance include: historical performance of comparable products developed with comparable technology; market performance of comparable titles; orders for the product prior to its release; general market conditions; and, for any sequel product, estimated performance based on the performance of the product on which the sequel is based. Further, as many of our capitalized intellectual property licenses extend for multiple products over multiple years, we also assess the recoverability of capitalized intellectual property license costs based on certain qualitative factors, such as the success of other products and/or entertainment vehicles utilizing the intellectual property, whether there are any future planned theatrical releases or television series based on the intellectual property, and the rights holder's continued promotion and exploitation of the intellectual property. Significant management judgments and estimates are utilized in assessing the recoverability of capitalized costs. In evaluating the recoverability of capitalized costs, the assessment of expected product performance utilizes forecasted sales amounts and estimates of additional costs to be incurred. If revised forecasted or actual product sales are less than the originally forecasted amounts utilized in the initial recoverability analysis, the net realizable value may be lower than originally estimated in any given quarter, which could result in an impairment charge. Material differences may result in the amount and timing of expenses for any period if management makes different judgments or utilizes different estimates in evaluating these qualitative factors.
Inventories	Inventories Inventories consist of materials (including manufacturing royalties paid to console manufacturers), labor, and freight-in and are stated at the lower of cost (weighted-average method) or net realizable value. Inventories are relieved on a weighted average cost method.
Property and equipment	Long-Lived Assets Property and Equipment. Property and equipment are recorded at cost and depreciated on a straight-line basis over the estimated useful life (i.e., 25 to 33 years for buildings, and 2 to 5 years for computer equipment, office furniture and other equipment) of the asset. When assets are retired or disposed of, the cost and accumulated depreciation thereon are removed and any resulting gains or losses are included in the consolidated statements of operations. Leasehold improvements are amortized using the straight-line method over the estimated life of the asset, not to exceed the length of the lease. Repair and maintenance costs are expensed as incurred.
Goodwill and Other Indefinite-Lived Assets	Goodwill and Other Indefinite-Lived Assets. We account for goodwill in accordance with ASC Topic 350. Under ASC Topic 350, goodwill is considered to have an indefinite life, and is carried at cost. Acquired trade names are assessed as indefinite lived assets as there are no foreseeable limits on the periods of time over which they are expected to contribute cash flows. Goodwill and acquired trade names are not amortized, but are subject to an annual impairment test, as well as between annual tests when events or circumstances indicate that the carrying value may not be recoverable. We perform our annual impairment testing at December 31st. Our annual goodwill impairment test is performed at the reporting unit level. We have determined our reporting units based on the guidance within ASC Subtopic 350-20, which provides that reporting units are generally operating segments or one reporting level below the operating segments. As of December 31, 2013 and 2012, our reporting units are the same as our operating segments: Activision, Blizzard, and Distribution. We test goodwill for possible impairment by first determining the fair value of the related reporting unit and comparing this value to the recorded net assets of the reporting unit, including goodwill. The fair value of our reporting units is determined using an income approach based on discounted cash flow models. In the event the recorded net assets of the reporting unit exceed the estimated fair value of such assets, we perform a second step to measure the amount of the impairment, which is equal to the amount by which the recorded goodwill exceeds the implied fair value of the goodwill after assessing the fair value of each of the assets and liabilities within the reporting unit. We have determined that no impairment has occurred at December 31, 2013 and 2012 based upon a set of assumptions regarding discounted future cash flows, which represent our best estimate of future performance at this time. We test acquired trade names for possible impairment by using a discounted cash flow model to estimate fair value. We have determined that no impairment has occurred at December 31, 2013 and 2012 based upon a set of assumptions regarding discounted future cash flows, which represent our best estimate of future performance at this time. Changes in our assumptions underlying our estimates of fair value, which will be a function of our future financial performance and changes in economic conditions, could result in future impairment charges.
Amortizable Intangible Assets	Amortizable Intangible Assets. Intangible assets subject to amortization are carried at cost less accumulated amortization, and amortized over the estimated useful life in proportion to the economic benefits received. Management evaluates the recoverability of our identifiable intangible assets and other long-lived assets in accordance with ASC Subtopic 360-10, which generally requires the assessment of these assets for recoverability when events or circumstances indicate a potential impairment exists. We considered certain events and circumstances in determining whether the carrying value of identifiable intangible assets and other long-lived assets, other than indefinite-lived intangible assets, may not be recoverable including, but not limited to: significant changes in performance relative to expected operating results; significant changes in the use of the assets; significant negative industry or economic trends; a significant decline in our stock price for a sustained period of time; and changes in our business strategy. If we determine that the carrying value may not be recoverable, we estimate the undiscounted cash flows to be generated from the use and ultimate disposition of these assets to determine whether an impairment exists. If an impairment is indicated based on a comparison of the assets' carrying values and the undiscounted cash flows, the impairment loss is measured as the amount by which the carrying amount of the assets exceeds the fair value of the assets. We have determined that there are no events or circumstances that indicate a potential impairment exists at December 31, 2013 and 2012.
Revenue Recognition	Revenue Recognition Revenue Arrangements with Multiple Deliverables Certain of our revenue arrangements have multiple deliverables, which we account for in accordance with ASC Topic 605 and Accounting Standards Update (“ASU”) 2009-13. These revenue arrangements include product sales consisting of both software and hardware deliverables (such as peripherals or other ancillary collectors' items sold together with physical “boxed” software) and our sales of World of Warcraft boxed products, expansion packs and value-added services, each of which is considered with the related subscription services for these purposes. Under ASC Topic 605 and ASU 2009-13, when a revenue arrangement contains multiple elements, such as hardware and software products, licenses and/or services, we allocate revenue to each element based on a selling price hierarchy. The selling price for a deliverable is based on its vendor-specific-objective-evidence (“VSOE”) if it is available, third-party evidence (“TPE”) if VSOE is not available, or best estimated selling price (“BESP”) if neither VSOE nor TPE is available. In multiple element arrangements where more-than-incidental software deliverables are included, revenue is allocated to each separate unit of accounting for each of the non-software deliverables and to the software deliverables as a group using the relative selling prices of each of the deliverables in the arrangement based on the aforementioned selling price hierarchy. If the arrangement contains more than one software deliverable, the arrangement consideration allocated to the software deliverables as a group is then allocated to each software deliverable using the guidance for recognizing software revenue. As noted above, when neither VSOE nor TPE is available for a deliverable, we use BESP. We do not have significant revenue arrangements that require BESP for the years ended December 31, 2013, 2012, and 2011. The inputs we use to determine the selling price of our significant deliverables include the actual price charged by the Company for a deliverable that the Company sells separately, which represents the VSOE, and the wholesale prices of the same or similar products, which represents TPE. The adoption of ASU 2009-13 on January 1, 2011 has not had a material impact on our financial statements. The pattern and timing of revenue recognition for deliverables and allocation of the arrangement consideration did not change upon the adoption of ASU 2009-13. Product Sales We recognize revenues from the sale of our products upon the transfer of title and risk of loss to our customers and once any performance obligations have been completed. Certain products are sold to customers with a “street date” (which is the earliest date these products may be sold by retailers). For these products, we recognize revenues on the later of the street date or the date the product is sold to the customer. Revenues from product sales are recognized after deducting the estimated allowance for returns and price protection. For our software products with online functionality, we evaluate whether that feature or functionality is more than an inconsequential separate deliverable, in addition to the software product. This evaluation is performed for each software product and digital download of a title or product add-ons (including digital downloadable content), when it is released. When we determine that a software title contains online functionality that constitutes a more-than-inconsequential separate service deliverable in addition to the product, which is principally because of the online functionality's importance to gameplay, we consider our performance obligation for this title to extend beyond the sale of the game. VSOE of fair value does not exist for the online functionality of some products, as we do not separately charge for this component of every title. As a result, we recognize all of the software-related revenues from the sale of any such title ratably over the estimated service period of the title. In addition, we initially defer the costs of sales for the title (excluding intangible asset amortization), and recognize the costs of sales as the related revenues are recognized. The costs of sales include manufacturing costs, software royalties and amortization, and intellectual property licenses. Determining whether the online functionality for a particular game constitutes a more-than-inconsequential deliverable, as well as the estimated service periods and product life over which to recognize the revenue and related costs of sales, is subjective and requires management's judgment. We recognize revenues from World of Warcraft boxed products, expansion packs and value-added services, in each case with the related subscription service revenues, ratably over the estimated service period beginning upon activation of the software and delivery of the related services. Revenues attributed to the sale of World of Warcraft boxed software and related expansion packs are classified as “Product sales,” whereas revenues attributable to subscriptions and other value-added services are classified as “Subscription, licensing, and other revenues.” For games where the online functionality is a more-than-inconsequential deliverable and games for which was have a hosted service arrangement, we determine the game's estimated service period with consideration of various data points, including the weighted-average number of days between players' first and last days played online, the average total hours played and the average number of days in which player activity stabilizes. We also consider known online trends, and the service periods of our previously released games and disclosed service periods for our competitor's games that are similar in nature. The estimated service periods for our current games range from five months to less than one year. For our software products with features we consider to be incidental to the overall product offering and are inconsequential deliverables, such as products which provide limited online features at no additional cost to the consumer, we recognize the related revenues upon the transfer of title and risk of loss of the product to our customer. With respect to online transactions, such as online downloads of titles or product add-ons that do not include a more-than-inconsequential separate service deliverable, revenues are recognized when the fee is paid by the online customer to purchase online content and the product is available for download or is activated for gameplay. In addition, persuasive evidence of an arrangement must exist and collection of the related receivable must be probable. Sales incentives and other consideration given by us to our customers, such as rebates and product placement fees, are considered adjustments of the selling price of our products and are reflected as reductions to revenues. Sales incentives and other consideration that represent costs incurred by us for assets or services received, such as the appearance of our products in a customer's national circular ad, are reflected as sales and marketing expenses when the benefit from the sales incentive is separable from sales to the same customer and we can reasonably estimate the fair value of the benefit. Subscription Revenues Subscription revenues are mostly derived from World of Warcraft. World of Warcraft is a game that is playable through Blizzard's servers and is generally sold on a subscription-only basis. For World of Warcraft, after the first month of free usage that is included with the World of Warcraft boxed software, the World of Warcraft end user may enter into a subscription agreement for additional future access. Revenues associated with the sales of subscriptions via boxed software and prepaid subscription cards, as well as prepaid subscriptions sales, are deferred until the subscription service is activated by the consumer and are then recognized ratably over the subscription period. Value-added service revenues associated with subscriptions are recognized ratably over the estimated service periods. Licensing Revenues Third-party licensees in Russia, China and Taiwan distribute and host Blizzard's World of Warcraft game in their respective countries under license agreements, for which they pay the Company a royalty. We recognize these royalties as revenues based on the end users' activation of the underlying prepaid time, if all other performance obligations have been completed, or based on usage by the end user, when we have continuing service obligations. We recognize any upfront licensing fees received over the term of the contracts. With respect to license agreements that provide customers the right to make multiple copies in exchange for guaranteed amounts, revenues are generally recognized upon delivery of a master copy. Per copy royalties on sales that exceed the guarantee are recognized as earned. In addition, persuasive evidence of an arrangement must exist and collection of the related receivable must be probable. Other Revenues Other revenues primarily include licensing activity of intellectual property other than software to third-parties. Revenues are recorded upon the receipt of licensee statements, or upon the receipt of cash, provided the license period has begun and all performance obligations have been completed. Revenues are recorded net of taxes assessed by governmental authorities that are both imposed on and concurrent with the specific revenue-producing transaction between us and our customer, such as sales and value added taxes.
Allowances for Returns, Price Protection, Doubtful Accounts, and Inventory Obsolescence	Allowances for Returns, Price Protection, Doubtful Accounts, and Inventory Obsolescence We closely monitor and analyze the historical performance of our various titles, the performance of products released by other publishers, market conditions, and the anticipated timing of other releases to assess future demand of current and upcoming titles. Initial volumes shipped upon title launch and subsequent reorders are evaluated with the goal of ensuring that quantities are sufficient to meet the demand from the retail markets, but at the same time are controlled to prevent excess inventory in the channel. We benchmark units to be shipped to our customers using historical and industry data. We may permit product returns from, or grant price protection to, our customers under certain conditions. In general, price protection refers to the circumstances in which we elect to decrease, on a short- or longer-term basis, the wholesale price of a product by a certain amount and, when granted and applicable, allow customers a credit against amounts owed by such customers to us with respect to open and/or future invoices. The conditions our customers must meet to be granted the right to return products or price protection include, among other things, compliance with applicable trading and payment terms, and consistent return of inventory and delivery of sell-through reports to us. We may also consider other factors, including the facilitation of slow-moving inventory and other market factors. Significant management judgments and estimates must be made and used in connection with establishing the allowance for returns and price protection in any accounting period based on estimates of potential future product returns and price protection related to current period product revenues. We estimate the amount of future returns and price protection for current period product revenues utilizing historical experience and information regarding inventory levels and the demand and acceptance of our products by the end consumer. The following factors are used to estimate the amount of future returns and price protection for a particular title: historical performance of titles in similar genres; historical performance of the hardware platform; historical performance of the franchise; console hardware life cycle; sales force and retail customer feedback; industry pricing; future pricing assumptions; weeks of on-hand retail channel inventory; absolute quantity of on-hand retail channel inventory; our warehouse on-hand inventory levels; the title's recent sell-through history (if available); marketing trade programs; and performance of competing titles. The relative importance of these factors varies among titles depending upon, among other items, genre, platform, seasonality, and sales strategy. Based upon historical experience, we believe that our estimates are reasonable. However, actual returns and price protection could vary materially from our allowance estimates due to a number of reasons including, among others, a lack of consumer acceptance of a title, the release in the same period of a similarly themed title by a competitor, or technological obsolescence due to the emergence of new hardware platforms. Material differences may result in the amount and timing of our revenues for any period if factors or market conditions change or if management makes different judgments or utilizes different estimates in determining the allowances for returns and price protection. For example, a 1% change in our December 31, 2013 allowance for sales returns, price protection and other allowances would have impacted net revenues by approximately $4 million. Similarly, management must make estimates as to the collectability of our accounts receivable. In estimating the allowance for doubtful accounts, we analyze the age of current outstanding account balances, historical bad debts, customer concentrations, customer creditworthiness, current economic trends, and changes in our customers' payment terms and their economic condition, as well as whether we can obtain sufficient credit insurance. Any significant changes in any of these criteria would affect management's estimates in establishing our allowance for doubtful accounts. We regularly review inventory quantities on-hand and in the retail channels. We write down inventory based on excess or obsolete inventories determined primarily by future anticipated demand for our products. Inventory write-downs are measured as the difference between the cost of the inventory and net realizable value, based upon assumptions about future demand, which are inherently difficult to assess and dependent on market conditions. At the point of a loss recognition, a new, lower cost basis for that inventory is established, and subsequent changes in facts and circumstances do not result in the restoration or increase in that newly established basis.
Shipping and Handling	Shipping and Handling Shipping and handling costs, which consist primarily of packaging and transportation charges incurred to move finished goods to customers, are included in “Cost of sales—product costs.”
Advertising Expenses	Advertising Expenses We expense advertising as incurred, except for production costs associated with media advertising, which are deferred and charged to expense when the related advertisement is run for the first time. Advertising expenses for the years ended December 31, 2013, 2012, and 2011 were $401 million, $396 million, and $343 million, respectively, and are included in “Sales and marketing expense” in the consolidated statements of operations.
Income Taxes	Income Taxes We record a tax provision for the anticipated tax consequences of the reported results of operations. In accordance with ASC Topic 740, the provision for income taxes is computed using the asset and liability method, under which deferred tax assets and liabilities are recognized for the expected future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating losses and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We evaluate deferred tax assets each period for recoverability. For those assets that do not meet the threshold of “more likely than not” that they will be realized in the future, a valuation allowance is recorded. 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.”
Foreign Currency Translation	Foreign Currency Translation All assets and liabilities of our foreign subsidiaries are translated into U.S. dollars at the exchange rate in effect at the balance sheet date, and revenue and expenses are translated at average exchange rates during the period. The resulting translation adjustments are reflected as a component of “Accumulated other comprehensive income (loss)” in shareholders' equity.
Earnings (Loss) Per Common Share	Earnings (Loss) Per Common Share “Basic earnings (loss) per common share” is computed by dividing income (loss) available to common shareholders by the weighted average number of common shares outstanding for the periods presented. “Diluted earnings per share” is computed by dividing income (loss) available to common shareholders by the weighted average number of common shares outstanding, increased by the weighted average number of common stock equivalents. Common stock equivalents are calculated using the treasury stock method and represent incremental shares issuable upon exercise of our outstanding options. However, potential common shares are not included in the denominator of the diluted earnings (loss) per share calculation when inclusion of such shares would be anti-dilutive, such as in a period in which a net loss is recorded. When we determine whether instruments granted in stock-based payment transactions are participating securities, unvested stock-based awards which include the right to receive non-forfeitable dividends or dividend equivalents are considered to participate with common stock in undistributed earnings. With participating securities, we are required to calculate basic and diluted earnings per common share amounts under the two-class method. The two-class method excludes from the earnings per common share calculation any dividends paid or owed to participating securities and any undistributed earnings considered to be attributable to participating securities.
Stock-Based Compensation	Stock-Based Compensation We account for stock-based compensation in accordance with ASC Topic 718-10, Compensation-Stock Compensation, and ASC Subtopic 505-50, Equity-Based Payments to Non-Employees. Stock-based compensation expense is recognized during the requisite service period (that is, the period for which the employee is being compensated) and is based on the value of stock-based payment awards after a reduction for estimated forfeitures. Forfeitures are estimated at the time of grant and are revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Stock-based compensation expense recognized in our consolidated statements of operations for the years ended December 31, 2013, 2012, and 2011 included both compensation expense for stock- based payment awards granted by Activision, Inc. prior to, but not yet vested as of July 9, 2008, based on the revalued fair value estimated at July 9, 2008, and compensation expense for the stock-based payment awards granted by us subsequent to July 9, 2008. We estimate the value of stock-based payment awards on the measurement date using a binomial-lattice model. Our determination of fair value of stock-based payment awards on the date of grant using an option-pricing model is affected by our stock price as well as assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, our expected stock price volatility over the term of the awards, and actual and projected employee stock option exercise behaviors. We generally determine the fair value of restricted stock rights (including restricted stock units, restricted stock awards and performance shares) based on the closing market price of the Company's common stock on the date of grant. Certain restricted stock rights granted to our employees and senior management vest based on the achievement of pre-established performance or market goals. We estimate the fair value of performance-based restricted stock rights at the closing market price of the Company's common stock on the date of grant. Each quarter, we update our assessment of the probability that the specified performance criteria will be achieved. We amortize the fair values of performance-based restricted stock rights over the requisite service period adjusted for estimated forfeitures for each separately vesting tranche of the award. We estimate the fair value of market-based restricted stock rights at the date of grant using a Monte Carlo valuation methodology and amortize those fair values over the requisite service period adjusted for estimated forfeitures for each separately vesting tranche of the award. The Monte Carlo methodology that we use to estimate the fair value of market-based restricted stock rights at the date of grant incorporates into the valuation the possibility that the market condition may not be satisfied. Provided that the requisite service is rendered, the total fair value of the market-based restricted stock rights at the date of grant must be recognized as compensation expense even if the market condition is not achieved. However, the number of shares that ultimately vest can vary significantly with the performance of the specified market criteria. See Note 15 of the Notes to Consolidated Financial Statements.

Summary of significant accounting policies (Policies)

12 Months Ended

Dec. 31, 2013

Summary of significant accounting policies

The accompanying consolidated financial statements include the accounts and operations of the Company. All intercompany accounts and transactions have been eliminated. The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates and assumptions.

Certain reclassifications have been made to prior year amounts to conform to the current period presentation.

The Company considers events or transactions that occur after the balance sheet date, but before the financial statements are issued, to provide additional evidence relative to certain estimates or to identify matters that require additional disclosures.

Results of Adjustment

During the year ended December 31, 2013, we identified through our internal processes that, in previous years, we erroneously under-accrued for certain indirect taxes for two countries in our Europe region. We performed an evaluation under SEC Staff Accounting Bulletin No. 108 and concluded the effect of this error was immaterial to prior years' financial statements as well as the full-year 2013 financial statements. As such, during the year ended December 31, 2013, we recorded an adjustment in our consolidated statements of operations which reduced “Total net revenues” by $8 million, “Interest and other investment income (expense), net” by $1 million, “Income before income tax expense” by $9 million, and “Net income” by $7 million. This adjustment reduced net revenues and income from operations before income tax expense by $8 million and $9 million, respectively, in each of our Blizzard segment, Europe region, and online subscriptions platform, as presented in Note 14 of the Notes to Consolidated Financial Statements. The adjustment increased “Accrued expenses and other liabilities” on our consolidated balance sheet by $9 million and represents a correction of an error. Operating cash flows were impacted by $9 million in 2013 when we settled the liability. The adjustment related to prior periods' net income as follows: (i) approximately $1 million for the quarter ended March 31, 2013; (ii) approximately $1 million for each quarter of 2012 (totaling approximately $4 million for the year ended December 31, 2012); (iii) approximately $2 million for the year ended December 31, 2011; and (iv) less than $1 million for the year ended December 31, 2010. Earnings per basic and diluted share were affected by less than $0.01 as a result of recording this adjustment.

During the year ended December 31, 2012, we identified through our internal processes that, in previous years, we erroneously over-recognized revenues for a country in our Europe region. We performed an evaluation under SEC Staff Accounting Bulletin No. 108 and concluded the effect of this error was immaterial to prior years' financial statements as well as the full-year 2012 financial statements. As such, during the year ended December 31, 2012, we recorded an adjustment in our consolidated statements of operations which reduced “Total net revenues” by $11 million and “Net income” by $8 million. This adjustment reduced net revenues and income from operations before income tax expense by $11 million in each of our Blizzard segment, Europe region, and online subscriptions platform, as presented in Note 14 of the Notes to Consolidated Financial Statements. The adjustment increased “Deferred revenues” on our consolidated balance sheet by $11 million and represents a correction of an error. There was no impact to operating cash flows. The adjustment related to prior periods' net income as follows: (i) approximately $1 million for the quarter ended March 31, 2012; (ii) less than $1 million for each quarter of 2011 (totaling approximately $3 million for the year ended December 31, 2011); (iii) approximately $2 million for the year ended December 31, 2010; and (iv) approximately $3 million for periods prior to the year ended December 31, 2010. Earnings per basic and diluted share were affected by less than $0.01 as a result of recording this adjustment.

Cash and cash equivalents

Cash and Cash Equivalents

We consider all money market funds and highly liquid investments with original maturities of three months or less at the time of purchase to be “Cash and cash equivalents.”

Investment securities

Investment Securities

Investments designated as available-for-sale securities are carried at fair value, which is based on quoted market prices for such securities, if available, or is estimated on the basis of quoted market prices of financial instruments with similar characteristics. Unrealized gains and losses of the Company's available-for-sale securities are excluded from earnings and are reported as a component of “Other comprehensive income (loss).”

Investments with original maturities greater than 90 days and remaining maturities of less than one year are normally classified within “Short-term investments.” In addition, investments with maturities beyond one year may be classified within “Short-term investments” if they are highly liquid in nature and represent the investment of cash that is available for current operations.

The specific identification method is used to determine the cost of securities disposed of, with realized gains and losses reflected in “Interest and other investment income (expense), net” in our consolidated statements of operations.

The Company's investments include auction rate securities (“ARS”). These ARS are variable rate bonds tied to short-term interest rates with long-term maturities. ARS have interest rates which reset through a modified Dutch auction at predetermined short-term intervals, typically every 7, 28, or 35 days. Interest on ARS is generally paid at the end of each auction process and is based upon the interest rate determined for the prior auction. Our investments in ARS are not material to our consolidated financial statements.

Restricted cash - compensating balances

Restricted Cash—Compensating Balances

Restricted cash is included within “Short-term investments” on the consolidated balance sheets. The majority of our restricted cash relates to a standby letter of credit required by one of our inventory manufacturers so that we can qualify for certain payment terms on our inventory purchases. Under the terms of this arrangement, we are required to maintain with the issuing bank a compensating balance, restricted as to use, of not less than the sum of the available amount of the letter of credit plus the aggregate amount of any drawings under the letter of credit that have been honored thereunder, but have not yet been reimbursed.

Financial instruments

Financial Instruments

The carrying amount of “Cash and cash equivalents,” “Accounts receivable,” “Accounts payable,” and “Accrued expenses” substantively approximate fair value due to the short-term nature of these accounts. Our investments in U.S. treasuries, government agency securities, and corporate bonds are carried at fair value, which is based on quoted market prices for such securities, if available, or is estimated on the basis of quoted market prices of financial instruments with similar characteristics. ARS are carried at fair value, which is estimated using an income-approach model.

The Company transacts business in various foreign currencies and has significant international sales and expenses denominated in foreign currencies, subjecting us to foreign currency risk. To mitigate our foreign currency exchange rate exposure resulting from our foreign currency-denominated monetary assets, liabilities, and earnings, we periodically enter into currency derivative contracts, principally forward contracts with maturities of generally less than one year. We do not use derivatives for speculative or trading purposes and we do not designate these derivatives as hedging instruments under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 815. Accordingly, we report the fair value of these contracts within “Other current assets” or “Other current liabilities” in our consolidated balance sheets and the changes in fair value within “General and administrative expenses” and “Interest and other investment income (expense), net” in our consolidated statements of operations, depending on the nature of the contracts. The fair value of foreign currency contracts are estimated based on the prevailing exchange rates of the various hedged currencies as of the end of the period.

Other-Than-Temporary Impairments

The Company regularly reviews its investments to determine whether a decline in fair value below the cost basis is an other-than-temporary impairment. If the decline is determined to be other-than-temporary, the cost basis of the investment is written down to fair value. For available-for-sale fixed maturity instruments where credit-related impairments exist, other-than-temporary impairments are reported in the consolidated statements of operations and non-credit impairments are reported as a component of “Other comprehensive income (loss).”

Concentration of Credit Risk

Our concentration of credit risk relates to depositors holding the Company's cash and cash equivalents and customers with significant accounts receivable balances.

Our cash and cash equivalents are invested primarily in money market funds consisting of short-term, high-quality debt instruments issued by governments and governmental organizations, financial institutions and industrial companies.

Our customer base includes retailers and distributors, including mass-market retailers, consumer electronics stores, discount warehouses, and game specialty stores in the U.S. and other countries worldwide. We perform ongoing credit evaluations of our customers and maintain allowances for potential credit losses. We generally do not require collateral or other security from our customers. We did not have any single customer that accounted for 10% or more of net revenues for the years ended December 31, 2013 and 2011. We had one customer for the Activision and Blizzard segments, GameStop, that accounted for approximately 10% of net revenues for the year ended December 31, 2012. We had one customer, Wal-Mart, that accounted for 24% and 20% of consolidated gross receivables at December 31, 2013 and 2012, respectively.

Software Development Costs and Intellectual Property Licenses

Software development costs include payments made to independent software developers under development agreements, as well as direct costs incurred for internally developed products.

We account for software development costs in accordance with ASC Subtopic 985-20, the guidance for costs of computer software to be sold, leased, or otherwise marketed. Software development costs are capitalized once technological feasibility of a product is established and such costs are determined to be recoverable. Technological feasibility of a product encompasses both technical design documentation and game design documentation, or the completed and tested product design and working model. Significant management judgments and estimates are utilized in the assessment of when technological feasibility is established. For products where proven technology exists, this may occur early in the development cycle. Technological feasibility is evaluated on a product-by-product basis. Prior to a product's release, if and when we believe capitalized costs are not recoverable, we expense the amounts as part of “Cost of sales—software royalties and amortization.” Capitalized costs for products that are cancelled or are expected to be abandoned are charged to “Product development expense” in the period of cancellation. Amounts related to software development which are not capitalized are charged immediately to “Product development expense.”

Commencing upon a product's release, capitalized software development costs are amortized to “Cost of sales—software royalties and amortization” based on the ratio of current revenues to total projected revenues for the specific product, generally resulting in an amortization period of six months or less.

Intellectual property license costs represent license fees paid to intellectual property rights holders for use of their trademarks, copyrights, software, technology, music or other intellectual property or proprietary rights in the development of our products. Depending upon the agreement with the rights holder, we may obtain the right to use the intellectual property in multiple products over a number of years, or alternatively, for a single product. Prior to a product's release, if and when we believe capitalized costs are not recoverable, we expense the amounts as part of “Cost of sales—intellectual property licenses.” Capitalized intellectual property costs for products that are cancelled or are expected to be abandoned are charged to “Product development expense” in the period of cancellation.

Commencing upon a product's release, capitalized intellectual property license costs are amortized to “Cost of sales—intellectual property licenses” based on the ratio of current revenues for the specific product to total projected revenues for all products in which the licensed property will be utilized. As intellectual property license contracts may extend for multiple years and can be used in multiple products to be released over a period beyond one year, the amortization of capitalized intellectual property license costs relating to such contracts may extend beyond one year.

We evaluate the future recoverability of capitalized software development costs and intellectual property licenses on a quarterly basis. For products that have been released in prior periods, the primary evaluation criterion is actual title performance. For products that are scheduled to be released in future periods, recoverability is evaluated based on the expected performance of the specific products to which the costs relate or in which the licensed trademark or copyright is to be used. Criteria used to evaluate expected product performance include: historical performance of comparable products developed with comparable technology; market performance of comparable titles; orders for the product prior to its release; general market conditions; and, for any sequel product, estimated performance based on the performance of the product on which the sequel is based. Further, as many of our capitalized intellectual property licenses extend for multiple products over multiple years, we also assess the recoverability of capitalized intellectual property license costs based on certain qualitative factors, such as the success of other products and/or entertainment vehicles utilizing the intellectual property, whether there are any future planned theatrical releases or television series based on the intellectual property, and the rights holder's continued promotion and exploitation of the intellectual property.

Significant management judgments and estimates are utilized in assessing the recoverability of capitalized costs. In evaluating the recoverability of capitalized costs, the assessment of expected product performance utilizes forecasted sales amounts and estimates of additional costs to be incurred. If revised forecasted or actual product sales are less than the originally forecasted amounts utilized in the initial recoverability analysis, the net realizable value may be lower than originally estimated in any given quarter, which could result in an impairment charge. Material differences may result in the amount and timing of expenses for any period if management makes different judgments or utilizes different estimates in evaluating these qualitative factors.

Inventories

Inventories consist of materials (including manufacturing royalties paid to console manufacturers), labor, and freight-in and are stated at the lower of cost (weighted-average method) or net realizable value. Inventories are relieved on a weighted average cost method.

Property and equipment

Long-Lived Assets

Property and Equipment. Property and equipment are recorded at cost and depreciated on a straight-line basis over the estimated useful life (i.e., 25 to 33 years for buildings, and 2 to 5 years for computer equipment, office furniture and other equipment) of the asset. When assets are retired or disposed of, the cost and accumulated depreciation thereon are removed and any resulting gains or losses are included in the consolidated statements of operations. Leasehold improvements are amortized using the straight-line method over the estimated life of the asset, not to exceed the length of the lease. Repair and maintenance costs are expensed as incurred.

Goodwill and Other Indefinite-Lived Assets

Goodwill and Other Indefinite-Lived Assets. We account for goodwill in accordance with ASC Topic 350. Under ASC Topic 350, goodwill is considered to have an indefinite life, and is carried at cost. Acquired trade names are assessed as indefinite lived assets as there are no foreseeable limits on the periods of time over which they are expected to contribute cash flows. Goodwill and acquired trade names are not amortized, but are subject to an annual impairment test, as well as between annual tests when events or circumstances indicate that the carrying value may not be recoverable. We perform our annual impairment testing at December 31st.

Our annual goodwill impairment test is performed at the reporting unit level. We have determined our reporting units based on the guidance within ASC Subtopic 350-20, which provides that reporting units are generally operating segments or one reporting level below the operating segments. As of December 31, 2013 and 2012, our reporting units are the same as our operating segments: Activision, Blizzard, and Distribution. We test goodwill for possible impairment by first determining the fair value of the related reporting unit and comparing this value to the recorded net assets of the reporting unit, including goodwill. The fair value of our reporting units is determined using an income approach based on discounted cash flow models. In the event the recorded net assets of the reporting unit exceed the estimated fair value of such assets, we perform a second step to measure the amount of the impairment, which is equal to the amount by which the recorded goodwill exceeds the implied fair value of the goodwill after assessing the fair value of each of the assets and liabilities within the reporting unit. We have determined that no impairment has occurred at December 31, 2013 and 2012 based upon a set of assumptions regarding discounted future cash flows, which represent our best estimate of future performance at this time.

We test acquired trade names for possible impairment by using a discounted cash flow model to estimate fair value. We have determined that no impairment has occurred at December 31, 2013 and 2012 based upon a set of assumptions regarding discounted future cash flows, which represent our best estimate of future performance at this time.

Changes in our assumptions underlying our estimates of fair value, which will be a function of our future financial performance and changes in economic conditions, could result in future impairment charges.

Amortizable Intangible Assets

Amortizable Intangible Assets. Intangible assets subject to amortization are carried at cost less accumulated amortization, and amortized over the estimated useful life in proportion to the economic benefits received.

Management evaluates the recoverability of our identifiable intangible assets and other long-lived assets in accordance with ASC Subtopic 360-10, which generally requires the assessment of these assets for recoverability when events or circumstances indicate a potential impairment exists. We considered certain events and circumstances in determining whether the carrying value of identifiable intangible assets and other long-lived assets, other than indefinite-lived intangible assets, may not be recoverable including, but not limited to: significant changes in performance relative to expected operating results; significant changes in the use of the assets; significant negative industry or economic trends; a significant decline in our stock price for a sustained period of time; and changes in our business strategy. If we determine that the carrying value may not be recoverable, we estimate the undiscounted cash flows to be generated from the use and ultimate disposition of these assets to determine whether an impairment exists. If an impairment is indicated based on a comparison of the assets' carrying values and the undiscounted cash flows, the impairment loss is measured as the amount by which the carrying amount of the assets exceeds the fair value of the assets. We have determined that there are no events or circumstances that indicate a potential impairment exists at December 31, 2013 and 2012.

Revenue Recognition

Revenue Arrangements with Multiple Deliverables

Certain of our revenue arrangements have multiple deliverables, which we account for in accordance with ASC Topic 605 and Accounting Standards Update (“ASU”) 2009-13. These revenue arrangements include product sales consisting of both software and hardware deliverables (such as peripherals or other ancillary collectors' items sold together with physical “boxed” software) and our sales of World of Warcraft boxed products, expansion packs and value-added services, each of which is considered with the related subscription services for these purposes.

Under ASC Topic 605 and ASU 2009-13, when a revenue arrangement contains multiple elements, such as hardware and software products, licenses and/or services, we allocate revenue to each element based on a selling price hierarchy. The selling price for a deliverable is based on its vendor-specific-objective-evidence (“VSOE”) if it is available, third-party evidence (“TPE”) if VSOE is not available, or best estimated selling price (“BESP”) if neither VSOE nor TPE is available. In multiple element arrangements where more-than-incidental software deliverables are included, revenue is allocated to each separate unit of accounting for each of the non-software deliverables and to the software deliverables as a group using the relative selling prices of each of the deliverables in the arrangement based on the aforementioned selling price hierarchy. If the arrangement contains more than one software deliverable, the arrangement consideration allocated to the software deliverables as a group is then allocated to each software deliverable using the guidance for recognizing software revenue.

As noted above, when neither VSOE nor TPE is available for a deliverable, we use BESP. We do not have significant revenue arrangements that require BESP for the years ended December 31, 2013, 2012, and 2011. The inputs we use to determine the selling price of our significant deliverables include the actual price charged by the Company for a deliverable that the Company sells separately, which represents the VSOE, and the wholesale prices of the same or similar products, which represents TPE. The adoption of ASU 2009-13 on January 1, 2011 has not had a material impact on our financial statements. The pattern and timing of revenue recognition for deliverables and allocation of the arrangement consideration did not change upon the adoption of ASU 2009-13.

Product Sales

We recognize revenues from the sale of our products upon the transfer of title and risk of loss to our customers and once any performance obligations have been completed. Certain products are sold to customers with a “street date” (which is the earliest date these products may be sold by retailers). For these products, we recognize revenues on the later of the street date or the date the product is sold to the customer. Revenues from product sales are recognized after deducting the estimated allowance for returns and price protection.

For our software products with online functionality, we evaluate whether that feature or functionality is more than an inconsequential separate deliverable, in addition to the software product. This evaluation is performed for each software product and digital download of a title or product add-ons (including digital downloadable content), when it is released.

When we determine that a software title contains online functionality that constitutes a more-than-inconsequential separate service deliverable in addition to the product, which is principally because of the online functionality's importance to gameplay, we consider our performance obligation for this title to extend beyond the sale of the game. VSOE of fair value does not exist for the online functionality of some products, as we do not separately charge for this component of every title. As a result, we recognize all of the software-related revenues from the sale of any such title ratably over the estimated service period of the title. In addition, we initially defer the costs of sales for the title (excluding intangible asset amortization), and recognize the costs of sales as the related revenues are recognized. The costs of sales include manufacturing costs, software royalties and amortization, and intellectual property licenses.

Determining whether the online functionality for a particular game constitutes a more-than-inconsequential deliverable, as well as the estimated service periods and product life over which to recognize the revenue and related costs of sales, is subjective and requires management's judgment.

We recognize revenues from World of Warcraft boxed products, expansion packs and value-added services, in each case with the related subscription service revenues, ratably over the estimated service period beginning upon activation of the software and delivery of the related services. Revenues attributed to the sale of World of Warcraft boxed software and related expansion packs are classified as “Product sales,” whereas revenues attributable to subscriptions and other value-added services are classified as “Subscription, licensing, and other revenues.”

For games where the online functionality is a more-than-inconsequential deliverable and games for which was have a hosted service arrangement, we determine the game's estimated service period with consideration of various data points, including the weighted-average number of days between players' first and last days played online, the average total hours played and the average number of days in which player activity stabilizes. We also consider known online trends, and the service periods of our previously released games and disclosed service periods for our competitor's games that are similar in nature.

The estimated service periods for our current games range from five months to less than one year.

For our software products with features we consider to be incidental to the overall product offering and are inconsequential deliverables, such as products which provide limited online features at no additional cost to the consumer, we recognize the related revenues upon the transfer of title and risk of loss of the product to our customer.

With respect to online transactions, such as online downloads of titles or product add-ons that do not include a more-than-inconsequential separate service deliverable, revenues are recognized when the fee is paid by the online customer to purchase online content and the product is available for download or is activated for gameplay. In addition, persuasive evidence of an arrangement must exist and collection of the related receivable must be probable.

Sales incentives and other consideration given by us to our customers, such as rebates and product placement fees, are considered adjustments of the selling price of our products and are reflected as reductions to revenues. Sales incentives and other consideration that represent costs incurred by us for assets or services received, such as the appearance of our products in a customer's national circular ad, are reflected as sales and marketing expenses when the benefit from the sales incentive is separable from sales to the same customer and we can reasonably estimate the fair value of the benefit.

Subscription Revenues

Subscription revenues are mostly derived from World of Warcraft. World of Warcraft is a game that is playable through Blizzard's servers and is generally sold on a subscription-only basis.

For World of Warcraft, after the first month of free usage that is included with the World of Warcraft boxed software, the World of Warcraft end user may enter into a subscription agreement for additional future access. Revenues associated with the sales of subscriptions via boxed software and prepaid subscription cards, as well as prepaid subscriptions sales, are deferred until the subscription service is activated by the consumer and are then recognized ratably over the subscription period. Value-added service revenues associated with subscriptions are recognized ratably over the estimated service periods.

Licensing Revenues

Third-party licensees in Russia, China and Taiwan distribute and host Blizzard's World of Warcraft game in their respective countries under license agreements, for which they pay the Company a royalty. We recognize these royalties as revenues based on the end users' activation of the underlying prepaid time, if all other performance obligations have been completed, or based on usage by the end user, when we have continuing service obligations. We recognize any upfront licensing fees received over the term of the contracts.

With respect to license agreements that provide customers the right to make multiple copies in exchange for guaranteed amounts, revenues are generally recognized upon delivery of a master copy. Per copy royalties on sales that exceed the guarantee are recognized as earned. In addition, persuasive evidence of an arrangement must exist and collection of the related receivable must be probable.

Other Revenues

Other revenues primarily include licensing activity of intellectual property other than software to third-parties. Revenues are recorded upon the receipt of licensee statements, or upon the receipt of cash, provided the license period has begun and all performance obligations have been completed.

Revenues are recorded net of taxes assessed by governmental authorities that are both imposed on and concurrent with the specific revenue-producing transaction between us and our customer, such as sales and value added taxes.

Allowances for Returns, Price Protection, Doubtful Accounts, and Inventory Obsolescence

We closely monitor and analyze the historical performance of our various titles, the performance of products released by other publishers, market conditions, and the anticipated timing of other releases to assess future demand of current and upcoming titles. Initial volumes shipped upon title launch and subsequent reorders are evaluated with the goal of ensuring that quantities are sufficient to meet the demand from the retail markets, but at the same time are controlled to prevent excess inventory in the channel. We benchmark units to be shipped to our customers using historical and industry data.

We may permit product returns from, or grant price protection to, our customers under certain conditions. In general, price protection refers to the circumstances in which we elect to decrease, on a short- or longer-term basis, the wholesale price of a product by a certain amount and, when granted and applicable, allow customers a credit against amounts owed by such customers to us with respect to open and/or future invoices. The conditions our customers must meet to be granted the right to return products or price protection include, among other things, compliance with applicable trading and payment terms, and consistent return of inventory and delivery of sell-through reports to us. We may also consider other factors, including the facilitation of slow-moving inventory and other market factors.

Significant management judgments and estimates must be made and used in connection with establishing the allowance for returns and price protection in any accounting period based on estimates of potential future product returns and price protection related to current period product revenues. We estimate the amount of future returns and price protection for current period product revenues utilizing historical experience and information regarding inventory levels and the demand and acceptance of our products by the end consumer. The following factors are used to estimate the amount of future returns and price protection for a particular title: historical performance of titles in similar genres; historical performance of the hardware platform; historical performance of the franchise; console hardware life cycle; sales force and retail customer feedback; industry pricing; future pricing assumptions; weeks of on-hand retail channel inventory; absolute quantity of on-hand retail channel inventory; our warehouse on-hand inventory levels; the title's recent sell-through history (if available); marketing trade programs; and performance of competing titles. The relative importance of these factors varies among titles depending upon, among other items, genre, platform, seasonality, and sales strategy.

Based upon historical experience, we believe that our estimates are reasonable. However, actual returns and price protection could vary materially from our allowance estimates due to a number of reasons including, among others, a lack of consumer acceptance of a title, the release in the same period of a similarly themed title by a competitor, or technological obsolescence due to the emergence of new hardware platforms. Material differences may result in the amount and timing of our revenues for any period if factors or market conditions change or if management makes different judgments or utilizes different estimates in determining the allowances for returns and price protection. For example, a 1% change in our December 31, 2013 allowance for sales returns, price protection and other allowances would have impacted net revenues by approximately $4 million.

Similarly, management must make estimates as to the collectability of our accounts receivable. In estimating the allowance for doubtful accounts, we analyze the age of current outstanding account balances, historical bad debts, customer concentrations, customer creditworthiness, current economic trends, and changes in our customers' payment terms and their economic condition, as well as whether we can obtain sufficient credit insurance. Any significant changes in any of these criteria would affect management's estimates in establishing our allowance for doubtful accounts.

We regularly review inventory quantities on-hand and in the retail channels. We write down inventory based on excess or obsolete inventories determined primarily by future anticipated demand for our products. Inventory write-downs are measured as the difference between the cost of the inventory and net realizable value, based upon assumptions about future demand, which are inherently difficult to assess and dependent on market conditions. At the point of a loss recognition, a new, lower cost basis for that inventory is established, and subsequent changes in facts and circumstances do not result in the restoration or increase in that newly established basis.

Shipping and Handling

Shipping and handling costs, which consist primarily of packaging and transportation charges incurred to move finished goods to customers, are included in “Cost of sales—product costs.”

Advertising Expenses

We expense advertising as incurred, except for production costs associated with media advertising, which are deferred and charged to expense when the related advertisement is run for the first time. Advertising expenses for the years ended December 31, 2013, 2012, and 2011 were $401 million, $396 million, and $343 million, respectively, and are included in “Sales and marketing expense” in the consolidated statements of operations.

Income Taxes

We record a tax provision for the anticipated tax consequences of the reported results of operations. In accordance with ASC Topic 740, the provision for income taxes is computed using the asset and liability method, under which deferred tax assets and liabilities are recognized for the expected future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating losses and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which the temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We evaluate deferred tax assets each period for recoverability. For those assets that do not meet the threshold of “more likely than not” that they will be realized in the future, a valuation allowance is recorded.

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.”

Foreign Currency Translation

All assets and liabilities of our foreign subsidiaries are translated into U.S. dollars at the exchange rate in effect at the balance sheet date, and revenue and expenses are translated at average exchange rates during the period. The resulting translation adjustments are reflected as a component of “Accumulated other comprehensive income (loss)” in shareholders' equity.

Earnings (Loss) Per Common Share

“Basic earnings (loss) per common share” is computed by dividing income (loss) available to common shareholders by the weighted average number of common shares outstanding for the periods presented. “Diluted earnings per share” is computed by dividing income (loss) available to common shareholders by the weighted average number of common shares outstanding, increased by the weighted average number of common stock equivalents. Common stock equivalents are calculated using the treasury stock method and represent incremental shares issuable upon exercise of our outstanding options. However, potential common shares are not included in the denominator of the diluted earnings (loss) per share calculation when inclusion of such shares would be anti-dilutive, such as in a period in which a net loss is recorded.

When we determine whether instruments granted in stock-based payment transactions are participating securities, unvested stock-based awards which include the right to receive non-forfeitable dividends or dividend equivalents are considered to participate with common stock in undistributed earnings. With participating securities, we are required to calculate basic and diluted earnings per common share amounts under the two-class method. The two-class method excludes from the earnings per common share calculation any dividends paid or owed to participating securities and any undistributed earnings considered to be attributable to participating securities.

Stock-Based Compensation

We account for stock-based compensation in accordance with ASC Topic 718-10, Compensation-Stock Compensation, and ASC Subtopic 505-50, Equity-Based Payments to Non-Employees. Stock-based compensation expense is recognized during the requisite service period (that is, the period for which the employee is being compensated) and is based on the value of stock-based payment awards after a reduction for estimated forfeitures. Forfeitures are estimated at the time of grant and are revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Stock-based compensation expense recognized in our consolidated statements of operations for the years ended December 31, 2013, 2012, and 2011 included both compensation expense for stock- based payment awards granted by Activision, Inc. prior to, but not yet vested as of July 9, 2008, based on the revalued fair value estimated at July 9, 2008, and compensation expense for the stock-based payment awards granted by us subsequent to July 9, 2008.

We estimate the value of stock-based payment awards on the measurement date using a binomial-lattice model. Our determination of fair value of stock-based payment awards on the date of grant using an option-pricing model is affected by our stock price as well as assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, our expected stock price volatility over the term of the awards, and actual and projected employee stock option exercise behaviors.

We generally determine the fair value of restricted stock rights (including restricted stock units, restricted stock awards and performance shares) based on the closing market price of the Company's common stock on the date of grant. Certain restricted stock rights granted to our employees and senior management vest based on the achievement of pre-established performance or market goals. We estimate the fair value of performance-based restricted stock rights at the closing market price of the Company's common stock on the date of grant. Each quarter, we update our assessment of the probability that the specified performance criteria will be achieved. We amortize the fair values of performance-based restricted stock rights over the requisite service period adjusted for estimated forfeitures for each separately vesting tranche of the award. We estimate the fair value of market-based restricted stock rights at the date of grant using a Monte Carlo valuation methodology and amortize those fair values over the requisite service period adjusted for estimated forfeitures for each separately vesting tranche of the award. The Monte Carlo methodology that we use to estimate the fair value of market-based restricted stock rights at the date of grant incorporates into the valuation the possibility that the market condition may not be satisfied. Provided that the requisite service is rendered, the total fair value of the market-based restricted stock rights at the date of grant must be recognized as compensation expense even if the market condition is not achieved. However, the number of shares that ultimately vest can vary significantly with the performance of the specified market criteria.

See Note 15 of the Notes to Consolidated Financial Statements.