aet:AdjustmentsToReconcileNetIncomeToNetCashProvidedByOperatingActivities Adjustments to Reconcile Net Income To Net Cash Provided By Operating Activities 0 aet:AuditOpinionTextBlock Audit Opinion [Text Block] The paragraph of the combined report that expresses an unqualified opinion, a qualified opinion, or a disclaimer of an opinion that the financial statements are in conformity with the basis of accounting (US GAAP, IFRS, etc.) on which they were prepared, and an opinion on the effectiveness of the system of internal controls over financial reporting. 0 aet:BenefitsAndExpenses Benefits and expenses: 0 aet:ChangesInAssetsAndLiabilities Changes In Assets And Liabilities 0 aet:CollateralOnInterestRateSwaps Collateral on interest rate swaps This item represents the change in cash that serves as collateral for our interest rate swaps. 2 aet:CommonSharesIssuedForBenefitPlansIncludingTaxBenefitShares Common Shares Issued For Benefit Plans Including Tax Benefit Shares Number of stock issued during the period as a result of stock-based compensation plans and employee stock purchase plans. 2 aet:CommonSharesIssuedForBenefitPlansIncludingTaxBenefitValues Common Shares Issued For Benefit Plans Including Tax Benefit Values Value of stock issued during the period as a result of stock-based compensation plans and employee stock purchase plans. 4 aet:CommonStockAndAdditionalPaidInCapitalMember Common Stock And Additional Paid In Capital [Member] 0 aet:CommonStockOutstandingMember Common Stock Outstanding [Member] 0 aet:CommonStockSharesIssuedAndOutstanding Common Stock, shares issued and outstanding Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury; and Total number of shares of common stock held by shareholders. May be all or portion of the number of common shares authorized. These shares represent the ownership interest of the common shareholders. Excludes common shares repurchased by the entity and held as Treasury shares. Shares outstanding equals shares issued minus shares held in treasury. Does not include common shares that have been repurchased. 2 aet:DebtTextBlock Debt [Text Block] Information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancings and noncompliance with debt covenants. Also contains a description of forward based contracts in which two parties agree to swap periodic payments that are fixed at the outset of the swap contract with variable payments based on a market interest rate (index rate) over a specified period. 1 aet:DiscontinuedProductsTextBlock Discontinued Products [Text Block] Prior to 1993, we sold single-premium annuities ("SPAs") and guaranteed investment contracts ("GICs"), primarily to employer sponsored pension plans. In 1993, we discontinued selling these products, and now we refer to these products as discontinued products. We discontinued selling these products because they were generating losses for us and we projected that they would continue to generate losses over their life (which is greater than 30 years), so we established a reserve for anticipated future losses at the time of discontinuance. This reserve represents the present value (at the risk-free rate of return at the time of discontinuance, consistent with the duration of the liabilities) of the difference between the expected cash flows from the assets supporting these products and the cash flows expected to be required to meet the obligations of the outstanding contracts. 1 aet:DividendRestrictionsAndStatutorySurplusTextBlock Dividend Restrictions And Statutory Surplus [Text Block] Disclosure of statutory restrictions on the payment of dividends as prescribed by the National Association of Insurance Commissioners or state regulatory authorities, amounts not available for future dividend payments, and amount of dividends paid. Amount of statutory capital and surplus computed using prescribed or permitted statutory accounting practice. 1 aet:FairValueMeasurementsTextBlock Fair Value Measurements [Text Block] This item represents the complete disclosure regarding the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Also, provides general information items required or determined to be disclosed with respect to the Companys fair value estimates for financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined). 1 aet:HealthCareAndInsuranceLiabilities Health care and insurance liabilities The net change during the reporting period of Health Care and Other Insurance Liabilities balances; shall be classified as cash flows from operating activities. 2 aet:IncomeBeforeIncomeTax Income before income tax Sum of income before income taxes. 4 aet:InvestmentsTextBlock Investments [Text Block] This item represents the entire disclosure related to Investments in Certain Debt and Equity Securities (and certain other trading assets) which include all debt and equity securities (other than those equity securities accounted for under the equity or cost methods of accounting) with readily determinable fair values. Other trading assets include assets that are carried on the balance sheet at fair value and held for trading purposes. A debt security represents a creditor relationship with an enterprise that is in the form of a security. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities (and other trading assets). Secondly, contains a description of noncontrolling interest which might include background information, terms of the ownership arrangement, and type and terms of equity interest owned by the noncontrolling interest holders. Thirdly, a description of the variable interest entity. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities. A VIE often holds financial assets, including loans or receivables, real estate or other property. A VIE may be essentially passive or it may engage in research and development or other activities on behalf of another company. Fourth, credit default swaps are also included. These are a type of swap transaction used as a credit derivative in which one party makes periodic payments to the other and receives the promise of a pay-off if a third party defaults. Finally, net investment income is also disclosed. This is the income earned from investments in securities and property, equipment and other capital assets. It includes rent from property and equipment, dividends from shares in corporations, and interest from bonds, loans, mortgages, derivatives, commercial paper, bank accounts, certificates of deposits, treasuries, and other financial securities. It does not include realized gains and losses on investments. 1 aet:LongTermFurturePolicyBenefits Long Term Furture Policy Benefits The sum of the known and estimated noncurrent amounts payable as of the balance sheet date to policyholders pertaining to insured events for long-duration contracts, which can be viewed as either (a) the present value of future benefits to be paid to or on behalf of policyholders and expenses less the present value of future net premiums payable under the insurance contracts or (b) the accumulated amount of net premiums already collected less the accumulated amount of benefits and expenses already paid to or on behalf of policyholders. 2 aet:LongTermPolicyholdersFunds Long Term Policyholders Funds The total liability as of the balance sheet date of noncurrent amounts due policy holders, excluding future policy benefits and claims, including unpaid policy dividends, retrospective refunds, and undistributed earnings on participating business. 2 aet:LongTermUnpaidClaims Long Term Unpaid Claims Noncurrent liability as of the balance sheet date for the estimated ultimate cost of settling claims and claim adjustment expense relating to insured events that have occurred on or before the balance sheet date for those liabilities owed to another party as a result of assuming another insurer's primary obligation. 2 aet:NetForeignCurrencyAndDerivativeGains Net Foreign Currency and derivative Gains This item represents the adjustment that results from the process of translating subsidiary financial statements and foreign equity investments into functional currency of the reporting entity and also the accumulated pretax change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. 4 aet:NotesToFinancialStatementsAbstract Notes To Financial Statements [Abstract] 0 aet:OperatingExpense Operating Expense Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. 0 aet:OtherNetFinancing Other Net Financing Transactions that result in no cash inflows or outflows in the period in which they occur, but affect net income and thus are removed when calculating net cash flow from financing activities using the indirect method. This element is used when there is not a more specific and appropriate element. 0 aet:ParentheticalDataForConsolidatedBalanceSheets Parenthetical Data For Consolidated Balance Sheets 0 aet:PendingAcquisitionTextBlock Pending Acquisition [Text Block] With respect to a pending business combination, provides a description of the business, which may include the industry, size, products and other important information. 1 aet:PhysicianClassActionSettlementInsuranceRelatedCharge Physician class action settlement insurance-related charge 0 aet:PolicyholdersFunds Policyholders' funds The total liability as of the balance sheet date of current amounts due to policy holders, excluding future policy benefits and claims, including unpaid policy dividends, retrospective refunds, and undistributed earnings on participating business. 2 aet:ReductionOfReserveForAnticipatedFutureLossesOnDiscontinuedProducts Reduction of reserve for anticipated future losses on discontinued products The amount of reduction taken against our reserve for anticipated future losses related to our discontinued products during the period. 4 aet:ShortTermFuturePolicyBenefits Short Term Future Policy Benefits The sum of the known and estimated amounts currently payable as of the balance sheet date to policyholders pertaining to insured events for long-duration contracts, which can be viewed as either (a) the present value of future benefits to be paid to or on behalf of policyholders and expenses less the present value of future net premiums payable under the insurance contracts or (b) the accumulated amount of net premiums already collected less the accumulated amount of benefits and expenses already paid to or on behalf of policyholders. 2 aet:ShortTermHealthCareCostsPayable Short Term Health Care Costs Payable Health Care Costs Payable represents the company's estimated obligation for health care services that have been rendered on behalf of insured customers but for which claims have not yet been received or processed as of the balance sheet date, and for liabilities for physician, hospital and other medical cost disputes as of the balance sheet date. 2 aet:ShortTermUnpaidClaims Short Term Unpaid Claims Current liability as of the balance sheet date for the estimated ultimate cost of settling claims and claim adjustment expense relating to insured events that have occurred on or before the balance sheet date for those liabilities owed to another party as a result of assuming another insurer's primary obligation. 2 aet:SubsequentEventDescriptionTextBlock Subsequent Event Description [Text Block] 0 aet:SummaryOfSignificantAccountingPoliciesTextBlock Summary of Significant Accounting Policies [Text Block] This element may be used to describe all significant accounting policies of the reporting entity. For a new accounting pronouncement that has been issued but not yet adopted, an entity's disclosure should (1) describe the new pronouncement, the date that adoption is required and the date that the entity plans to adopt, if earlier; (2) discuss the methods of adoption allowed by the pronouncement and the method expected to be utilized by the entity, if determined; (3) discuss the impact that adoption of the pronouncement is expected to have on the financial statements of the entity, unless such impact is not known or reasonably estimable (in which case, a statement to that effect should be made) and; (4) disclose the potential impact of other significant matters that the entity believes might result from the adoption of the pronouncement (for example, technical violations of debt covenant agreements and planned or intended changes in business practices.) 1 aet:SupplementalInformationAbstract Supplemental Information [Abstract] 0 aet:TotalBenefitsAndExpenses Total benefits and expenses Total amount of benefit and other expenses incurred during the period. 4