SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business Aflac Incorporated (the Parent Company) and its subsidiaries (collectively, the Company) primarily sell supplemental health and life insurance in the United States and Japan. The Company's insurance business is marketed and administered through American Family Life Assurance Company of Columbus (Aflac), which operates in the United States (Aflac U.S.) and as a branch in Japan (Aflac Japan). Most of Aflac's policies are individually underwritten and marketed through independent agents. Additionally, Aflac U.S. markets and administers group products through Continental American Insurance Company (CAIC), branded as Aflac Group Insurance. Our insurance operations in the United States and our branch in Japan service the two markets for our insurance business. Aflac Japan's revenues, including realized gains and losses on its investment portfolio, accounted for 75% and 78% of the Company's total revenues in the nine-month periods ended September 30, 2013, and 2012, respectively. The percentage of the Company's total assets attributable to Aflac Japan was 85% at September 30, 2013, and 87% at December 31, 2012. Basis of Presentation We prepare our financial statements in accordance with U.S. generally accepted accounting principles (GAAP). These principles are established primarily by the Financial Accounting Standards Board (FASB). In these Notes to the Consolidated Financial Statements, references to GAAP issued by the FASB are derived from the FASB Accounting Standards Codification^TM (ASC). The preparation of financial statements in conformity with GAAP requires us to make estimates when recording transactions resulting from business operations based on currently available information. The most significant items on our balance sheet that involve a greater degree of accounting estimates and actuarial determinations subject to changes in the future are the valuation of investments, deferred policy acquisition costs, liabilities for future policy benefits and unpaid policy claims, and income taxes. These accounting estimates and actuarial determinations are sensitive to market conditions, investment yields, mortality, morbidity, commission and other acquisition expenses, and terminations by policyholders. As additional information becomes available, or actual amounts are determinable, the recorded estimates will be revised and reflected in operating results. Although some variability is inherent in these estimates, we believe the amounts provided are adequate. The unaudited consolidated financial statements include the accounts of the Parent Company, its subsidiaries and those entities required to be consolidated under applicable accounting standards. All material intercompany accounts and transactions have been eliminated. In the opinion of management, the accompanying unaudited consolidated financial statements of the Company contain all adjustments, consisting of normal recurring accruals, which are necessary to fairly present the consolidated balance sheets as of September 30, 2013, and December 31, 2012, the consolidated statements of earnings and comprehensive income (loss) for the three- and nine-month periods ended September 30, 2013, and 2012, and the consolidated statements of shareholders' equity and cash flows for the nine-month periods ended September 30, 2013, and 2012. Results of operations for interim periods are not necessarily indicative of results for the entire year. As a result, these financial statements should be read in conjunction with the financial statements and notes thereto included in our annual report to shareholders for the year ended December 31, 2012.
Income Taxes	Income Taxes: Income tax provisions are generally based on pretax earnings reported for financial statement purposes, which differ from those amounts used in preparing our income tax returns. Deferred income taxes are recognized for temporary differences between the financial reporting basis and income tax basis of assets and liabilities, based on enacted tax laws and statutory tax rates applicable to the periods in which we expect the temporary differences to reverse. We record deferred tax assets for tax positions taken based on our assessment of whether the tax position is more likely than not to be sustained upon examination by taxing authorities. A valuation allowance is established for deferred tax assets when it is more likely than not that an amount will not be realized. In the second quarter of 2013, we recorded a valuation allowance of $237 million related to the deferred tax assets associated with our unrealized investment losses recorded in other comprehensive income. In the third quarter of 2013, we released this $237 million valuation allowance because it was more likely than not that the deferred tax assets related to unrealized investment losses will be realized in the future. As discussed in the Translation of Foreign Currencies section in Note 1 of the Notes to the Consolidated Financial Statements in our annual report to shareholders for the year ended December 31, 2012, Aflac Japan maintains certain dollar-denominated investments. While there are no translation effects to record in other comprehensive income (loss), the deferred tax expense or benefit associated with foreign exchange gains or losses on this portfolio is recognized in other comprehensive income (loss) until the securities mature or are sold. Total income tax expense (benefit) related to items of other comprehensive income (loss) included a tax benefit of $38 million during the three-month period ended September 30, 2013, and a tax benefit of $86 million during the three-month period ended September 30, 2012, for these dollar-denominated investments. Excluding these amounts from total taxes on other comprehensive income (loss) would result in an effective income tax rate on pretax other comprehensive income (loss) of (102.3)% and 34.4% in the three-month periods ended September 30, 2013 and 2012, respectively. In addition, excluding the release of the tax valuation allowance in the three-month period ended September 30, 2013, the effective income tax rate on pretax other comprehensive income (loss) would have been 38.8%. Total income tax expense (benefit) related to items of other comprehensive income (loss) included tax expense of $614 million during the nine-month period ended September 30, 2013, and a tax benefit of $25 million during the nine-month period ended September 30, 2012, for these dollar-denominated investments. Excluding these amounts from total taxes on other comprehensive income (loss) would result in an effective income tax rate on pretax other comprehensive income (loss) of 38.1% and 35.2% in the nine-month periods ended September 30, 2013 and 2012, respectively.
Reinsurance	Reinsurance: We enter into reinsurance agreements with other companies in the normal course of business. For each of our reinsurance agreements, we determine if the agreement provides indemnification against loss or liability relating to insurance risk in accordance with applicable accounting standards. Reinsurance premiums and benefits paid or provided are accounted for on bases consistent with those used in accounting for the original policies issued and the terms of the reinsurance contracts. Premiums, benefits and deferred acquisition costs (DAC) are reported net of insurance ceded. See Note 6 of the Notes to the Consolidated Financial Statements for additional information.
Reclassification Policy	Reclassifications: Certain reclassifications have been made to prior-year amounts to conform to current-year reporting classifications. These reclassifications had no impact on net earnings or total shareholders' equity.
Recently Adopted Accounting Pronouncements	New Accounting Pronouncements Recently Adopted Accounting Pronouncements Derivatives and hedging: In July 2013, the FASB issued an update which allows entities to use the Federal Funds Effective Swap Rate, also referred to as the Overnight Index Swap Rate (OIS), as a benchmark interest rate for hedge accounting purposes. Previously the only acceptable benchmark rates for hedge accounting purposes under GAAP were U.S. Treasury rates and the London Interbank Offered Rate (LIBOR) swap rate. This update reflects the evolution of market hedging practices and is intended to provide more flexibility in hedging interest rate risk. We adopted this guidance in the third quarter of 2013 on a prospective basis for qualifying new or redesignated hedging relationships entered into on or after the effective date of July 17, 2013. The adoption of the guidance had no impact on our financial position or results of operations. Reporting of amounts reclassified out of accumulated other comprehensive income: In February 2013, the FASB issued guidance that requires reclassification adjustments for items that are reclassified out of accumulated other comprehensive income to net income to be presented in statements where the components of net income and the components of other comprehensive income are presented or in the footnotes to the financial statements. Additionally, the amendment requires cross-referencing to other disclosures currently required for other reclassification items. We adopted this guidance as of January 1, 2013. The adoption of this guidance impacted our financial statement disclosures, but it did not have an impact on our financial position or results of operations. Disclosures about offsetting assets and liabilities: In December 2011, the FASB issued guidance to amend the disclosure requirements about offsetting assets and liabilities. The new guidance essentially clarifies the FASB's intent concerning the application of existing offsetting disclosure requirements. Entities are required to disclose gross and net information about both instruments and transactions eligible for offset in the statement of financial position and instruments and transactions when those activities are subject to an agreement similar to a master netting arrangement. The scope of this guidance was clarified and revised in January 2013 to apply to derivatives, repurchase agreements, reverse repurchase agreements, securities borrowing and securities lending arrangements. The objective of this disclosure is to move toward consistency between U.S. GAAP and International Financial Reporting Standards (IFRS). We adopted this guidance as of January 1, 2013. The adoption of this guidance impacted our financial statement disclosures, but it did not have an impact on our financial position or results of operations. Presentation of comprehensive income: In June 2011, the FASB issued guidance to amend the presentation of comprehensive income. The amendment requires that all non-owner changes in shareholders' equity be presented either in a single continuous statement of comprehensive income or in two separate but consecutive statements. We adopted this guidance as of January 1, 2012 and elected the option to report comprehensive income in two separate but consecutive statements. The adoption of this guidance did not have an impact on our financial position or results of operations. Fair value measurements and disclosures: In May 2011, the FASB issued guidance to amend the fair value measurement and disclosure requirements. Most of the amendments are clarifications of the FASB's intent about the application of existing fair value measurement and disclosure requirements. Other amendments change a particular principle or requirement for measuring fair value or disclosing information about fair value measurements. The new fair value measurement disclosures include additional quantitative and qualitative disclosures for Level 3 measurements, including a qualitative sensitivity analysis of fair value to changes in unobservable inputs, and categorization by fair value hierarchy level for items for which the fair value is only disclosed. We adopted this guidance as of January 1, 2012. The adoption of this guidance impacted our financial statement disclosures, but it did not affect our financial position or results of operations. Accounting for costs associated with acquiring or renewing insurance contracts: In October 2010, the FASB issued amended accounting guidance on accounting for costs associated with acquiring or renewing insurance contracts. Under the previous guidance, costs that varied with and were primarily related to the acquisition of a policy were deferrable. Under the amended guidance, only incremental direct costs associated with the successful acquisition of a new or renewal contract may be capitalized, and direct-response advertising costs may be capitalized only if they meet certain criteria. This guidance is effective on a prospective or retrospective basis for interim and annual periods beginning after December 15, 2011. We retrospectively adopted this guidance as of January 1, 2012. The retrospective adoption of this accounting standard resulted in an after-tax cumulative reduction to retained earnings of $391 million and an after-tax cumulative reduction to unrealized foreign currency translation gains in accumulated other comprehensive income of $67 million, resulting in a total reduction to shareholders' equity of $458 million as of December 31, 2009 (the opening balance sheet date in our annual report on Form 10-K for the year ended December 31, 2012). The adoption of this accounting standard had an immaterial impact on net income in 2011 and for all preceding years
Description of Accounting Pronouncements Pending Adoption	Accounting Pronouncements Pending Adoption Presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists: In July 2013, the FASB issued guidance to amend the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The new guidance essentially states that an unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. However, to the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. This accounting standard applies to all entities that have unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. This guidance is effective for annual reporting periods beginning on or after December 15, 2013, and interim periods within those annual periods and requires prospective presentation for all comparative periods presented. The adoption of this guidance will not have a significant impact on our financial statements.

Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.

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Disclosure of reinsurance accounting policy, for example, but not limited to, description of the methodologies and assumptions underlying determination of reinsurance recoverables, reinsurance payables and retention policy.

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