Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2014

Accounting Policies [Abstract]

Basis of Presentation [Policy Text Block]

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information. The financial statements include all adjustments (consisting only of normal recurring adjustments) that the management of Gilead Sciences, Inc. (Gilead, we or us) believes are necessary for a fair presentation of the periods presented. These interim financial results are not necessarily indicative of results expected for the full fiscal year or for any subsequent interim period.

The accompanying Condensed Consolidated Financial Statements include the accounts of Gilead, our wholly-owned subsidiaries and our joint ventures with Bristol-Myers Squibb Company (BMS), for which we are the primary beneficiary. We record a noncontrolling interest in our Condensed Consolidated Financial Statements to reflect BMS’s interest in the joint ventures. All intercompany transactions have been eliminated. The Condensed Consolidated Financial Statements include the results of companies acquired by us from the date of each acquisition for the applicable reporting periods.

The accompanying Condensed Consolidated Financial Statements and related Notes to Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the related notes thereto for the year ended December 31, 2013, included in our Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission.

Significant Accounting Policies, Estimates and Judgments [Policy Text Block]

Significant Accounting Policies, Estimates and Judgments

The preparation of these Condensed Consolidated Financial Statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosures. On an ongoing basis, management evaluates its significant accounting policies or estimates. We base our estimates on historical experience and on various market specific and other relevant assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ significantly from these estimates.

Concentrations of Risk [Policy Text Block]

Concentrations of Risk

We are subject to credit risk from our portfolio of cash equivalents and marketable securities. Under our investment policy, we limit amounts invested in such securities by credit rating, maturity, industry group, investment type and issuer, except for securities issued by the U.S. government. We are not exposed to any significant concentrations of credit risk from these financial instruments. The goals of our investment policy, in order of priority, are as follows: safety and preservation of principal and diversification of risk; liquidity of investments sufficient to meet cash flow requirements; and a competitive after-tax rate of return.

We are also subject to credit risk from our accounts receivable related to our product sales. The majority of our trade accounts receivable arises from product sales in the United States and Europe.

As of June 30, 2014, our accounts receivable in Southern Europe, specifically Greece, Italy, Portugal and Spain, totaled approximately $652.4 million, of which $173.0 million were greater than 120 days past due and $53.6 million were greater than 365 days past due. To date, we have not experienced significant losses with respect to the collection of our accounts receivable. We believe that our allowance for doubtful accounts was adequate at June 30, 2014.

Recent Accounting Pronouncement [Policy Text Block]

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board, jointly with the International Accounting Standards Board, issued a comprehensive new standard on revenue recognition from contracts with customers. The standard's core principle is that a reporting entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying this new guidance to contracts within its scope, an entity will: (1) identify the contract(s) with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when (or as) the entity satisfies a performance obligation. Additionally, this new guidance will require significantly expanded revenue recognition disclosures. This guidance will become effective for us beginning in the first quarter of 2017. Early application is not permitted. Entities have the option of using either a full retrospective or a modified retrospective approach to adopt this new guidance. We are currently evaluating the impact of our pending adoption of this standard on our Condensed Consolidated Financial Statements.