Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2018
Policy (Text Block) [Abstract]
Description of new accounting pronouncements adopted	Effective January 1, 2018, we adopted new revenue recognition guidance issued by the FASB related to contracts with customers. The scope of the new guidance excludes financial instruments such as credit and charge card arrangements. We elected to adopt the standard using the full retrospective method, which we believe is most useful to our investors. Under the full retrospective method, we are applying the standard back to January 1, 2016. As shown below, the most significant impacts of adoption are changes to the classification of certain revenues and expenses, including certain credit and charge card related costs previously netted against discount revenue, such as Card Member cash-back reward costs and statement credits, corporate incentive payments, as well as payments to third-party GNS card issuing partners. Under the new revenue standard, these costs are not considered components of the transaction price of our card acceptance agreements with merchants and thus are not netted against discount revenue, but instead are recognized as expenses. Our payments to third-party GNS card issuing partners are presented net of related revenues earned from the partners. The adoption of the new guidance also resulted in changes to the recognition timing of certain revenues, the impact of which is not material to net income. Similarly, the adoption did not have a material impact on our financial position or cash flows. We had no material contract assets, contract liabilities or deferred contract costs recorded on the Consolidated Balance Sheet as of December 31, 2018 and 2017. Contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. In adopting the guidance, we implemented changes to our accounting policies, business processes, systems and internal controls to support the recognition, measurement and disclosure requirements under the new standard. Such changes were not material. In January 2016, the FASB issued new accounting guidance on the recognition and measurement of financial assets and financial liabilities, which was effective and adopted by us as of January 1, 2018. The guidance makes targeted changes to GAAP; specifically to the classification and measurement of equity securities, and to certain disclosure requirements associated with the fair value of financial assets and liabilities. This applies to investments we make in non-public companies in the ordinary course of business, which historically were recognized under the cost method of accounting. These investments will be prospectively adjusted through earnings for observable price changes upon the identification of identical or similar transactions of the same company. The adoption of the guidance did not have a material impact on our financial position, results of operations and cash flows. We implemented changes to our accounting policies, business processes and internal controls in support of the new guidance. Such changes were not material. In August 2017, the FASB issued new accounting guidance providing targeted improvements to the accounting for hedging activities, effective January 1, 2019, with early adoption permitted in any interim period or fiscal year before the effective date. The guidance introduces a number of amendments, several of which are optional, that are designed to simplify the application of hedge accounting, improve financial statement transparency and more closely align hedge accounting with an entity’s risk management strategies. Effective January 1, 2018, we adopted the guidance, with no material impact on our financial position, results of operations and cash flows, along with associated changes to our accounting policies, business processes and internal controls in support of the new guidance. Such changes were not material.
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements are prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Significant intercompany transactions are eliminated. We consolidate entities in which we hold a “controlling financial interest.” For voting interest entities, we are considered to hold a controlling financial interest when we are able to exercise control over the investees’ operating and financial decisions. For variable interest entities (VIEs), the determination of which is based on the amount and characteristics of the entity’s equity, we are considered to hold a controlling financial interest when we are determined to be the primary beneficiary. A primary beneficiary is the party that has both: (1) the power to direct the activities that most significantly impact that VIE’s economic performance, and (2) the obligation to absorb the losses of, or the right to receive the benefits from, the VIE that could potentially be significant to that VIE. Entities in which our voting interest in common equity does not provide it with control, but allows us to exert significant influence over operating and financial decisions, are accounted for under the equity method. We also have investments in equity securities where our voting interest is below the level of significant influence, including investments that we make in non-public companies in the ordinary course of business. Such investments are initially recorded at cost and adjusted to fair value through earnings for observable price changes in orderly transactions for identical or similar transactions of the same company or if they are determined to be impaired. See Note 5 for the accounting policy for our marketable equity securities.
Foreign Currency	Foreign Currency Monetary assets and liabilities denominated in foreign currencies are translated into U.S. dollars based upon exchange rates prevailing at the end of the reporting period; non-monetary assets and liabilities are translated at the historic exchange rate at the date of the transaction; revenues and expenses are translated at the average month-end exchange rates during the year. Resulting translation adjustments, along with any related qualifying hedge and tax effects, are included in accumulated other comprehensive income (loss) (AOCI), a component of shareholders’ equity. Translation adjustments, including qualifying hedge and tax effects, are reclassified to earnings upon the sale or substantial liquidation of investments in foreign operations. Gains and losses related to transactions in a currency other than the functional currency are reported net in Other expenses, in our Consolidated Statements of Income.
Amounts Based on Estimates and Assumptions	Amounts Based on Estimates and Assumptions Accounting estimates are an integral part of the Consolidated Financial Statements. These estimates are based, in part, on management’s assumptions concerning future events. Among the more significant assumptions are those that relate to reserves for Card Member losses on loans and receivables, Membership Rewards liability, goodwill and income taxes. These accounting estimates reflect the best judgment of management, but actual results could differ.
Total Revenues Net of Interest Expense	Discount Revenue Discount revenue primarily represents the amount we earn on transactions occurring at merchants that have entered into a card acceptance agreement with us, or a Global Network Services (GNS) partner or other third-party merchant acquirer, for facilitating transactions between the merchants and Card Members. The amount of fees charged for accepting our cards as payment for goods or services, or merchant discount, varies with, among other factors, the industry in which the merchant conducts business, the merchant’s overall American Express-related transaction volume, the method of payment, the settlement terms with the merchant, the method of submission of transactions and, in certain instances, the geographic scope of the card acceptance agreement between the merchant and us (e.g., local or global) and the transaction amount. The merchant discount is generally deducted from the payment to the merchant and recorded as discount revenue at the time the Card Member transaction occurs. The card acceptance agreements, which include the agreed-upon terms for charging the merchant discount fee, vary in duration. Our contracts with small- and medium-sized merchants generally have no fixed contractual duration, while those with large merchants are generally for fixed periods, which typically range from three to seven years in duration. Our fixed-period agreements may include auto-renewal features, which may allow the existing terms to continue beyond the stated expiration date until a new agreement is reached. We satisfy our obligations under these agreements over the contract term, often on a daily basis, including through the processing of Card Member transactions and the availability of our payment network. In cases where the merchant acquirer is a third party (which is the case, for example, under our OptBlue program, or with certain of our GNS partners), we receive a network rate fee in our settlement with the merchant acquirer, which is individually negotiated between us and that merchant acquirer and is recorded as discount revenue at the time the Card Member transaction occurs. In our role as the operator of the American Express network, we also settle with merchants on behalf of our GNS card issuing partners, who in turn receive an issuer rate that is individually negotiated between that issuer and us and is recorded as expense in Marketing and business development (see below) or as contra-revenue in Other revenue. Net Card Fees Net card fees represent revenue earned from annual card membership fees, which vary based on the type of card and the number of cards for each account. These fees, net of acquisition costs and a reserve for projected refunds for Card Member cancellations, are deferred and recognized on a straight-line basis over the twelve-month card membership period as Net card fees in the Consolidated Statements of Income. The unamortized net card fee balance is reported in Other liabilities on the Consolidated Balance Sheets (refer to Note 10). Other Fees and Commissions Other fees and commissions includes certain fees charged to Card Members, including delinquency fees and foreign currency conversion fees, which are primarily recognized in the period in which they are charged to the Card Member. Other fees and commissions also includes Membership Rewards program fees, which are deferred and recognized over the period covered by the fee, typically one year, the unamortized portion of which is included in Other liabilities on the Consolidated Balance Sheets. In addition, Other fees and commissions includes loyalty coalition-related fees, travel commissions and fees and service fees earned from merchants, that are recognized when the service is performed, which is generally in the period the fee is charged. Refer to Note 19 for additional information. Contra-revenue Payments made pursuant to contractual arrangements with our merchants, GNS partners, and other customers are classified as contra-revenue, except where we receive goods, services or other benefits for which the fair value is determinable and measurable, in which case they are recorded as expense. Interest Income Interest on Card Member loans is assessed using the average daily balance method. Unless the loan is classified as non-accrual, interest is recognized based upon the principal amount outstanding, in accordance with the terms of the applicable account agreement, until the outstanding balance is paid, or written off. Interest and dividends on investment securities primarily relate to our performing fixed-income securities. Interest income is recognized as earned using the effective interest method, which adjusts the yield for security premiums and discounts, fees and other payments, so that a constant rate of return is recognized on the investment security’s outstanding balance. Amounts are recognized until securities are in default or when it becomes likely that future interest payments will not be made as scheduled. Interest on deposits with banks and other is recognized as earned, and primarily relates to the placement of cash, in excess of near-term funding requirements, in interest-bearing time deposits, overnight sweep accounts, and other interest-bearing demand and call accounts. Interest Expense Interest expense includes interest incurred primarily to fund Card Member loans and receivables, general corporate purposes and liquidity needs, and is recognized as incurred. Interest expense is divided principally into two categories: (i) deposits, which primarily relates to interest expense on deposits taken from customers and institutions, and (ii) debt, which primarily relates to interest expense on our long-term debt and short-term borrowings, as well as the realized impact of derivatives used to hedge interest rate risk on our long-term debt.
Expenses	Marketing and Business Development As further described below under “Recently Adopted Accounting Standards,” effective January 1, 2018, in conjunction with the adoption of the new revenue recognition standard, the previously disclosed “Marketing and promotion” line on the Consolidated Statements of Income was changed to “Marketing and business development” to reflect the inclusion of certain reclassified costs from contra-discount revenue and Other expenses. Marketing and business development provides a more comprehensive view of costs related to building and growing our business, including the reclassified costs. Marketing and business development expense includes costs incurred in the development and initial placement of advertising, which are expensed in the year in which the advertising first takes place. Also included in Marketing and business development expense are Card Member statement credits for qualifying charges on eligible card accounts, corporate incentive payments earned on achievement of preset targets, and certain payments to GNS card issuing partners. These costs are generally expensed as incurred. Card Member Rewards We issue charge and credit cards that allow Card Members to participate in various rewards programs (e.g., Membership Rewards, cobrand and cash back). Rewards expense is recognized in the period Card Members earn rewards, generally by spending on their enrolled card products. We record a Card Member rewards liability that represents the estimated cost of points earned that are expected to be redeemed. Pursuant to cobrand agreements, we make payments to our cobrand partners based primarily on the amount of Card Member spending and corresponding rewards earned on such spending and, under certain arrangements, on the number of accounts acquired and retained. The partner is then liable for providing rewards to the Card Member under the cobrand partner’s own loyalty program. Card Member rewards liabilities are impacted over time by enrollment levels, attrition, the volume of points earned and redeemed, and the associated redemption costs. Changes in the Card Member rewards liabilities during the period are taken as an increase or decrease to the Card Member rewards expense in the Consolidated Statement of Income. Effective January 1, 2018, in conjunction with the adoption of the new revenue recognition standard, Card Member rewards also includes cash-back rewards, which were reclassified from contra discount revenue.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash and amounts due from banks, interest-bearing bank balances, including securities purchased under resale agreements, and other highly liquid investments with original maturities of 90 days or less.
Premises and Equipment	Premises and Equipment Premises and equipment, including leasehold improvements, are carried at cost less accumulated depreciation. Costs incurred during construction are capitalized and are depreciated once an asset is placed in service. Depreciation is generally computed using the straight-line method over the estimated useful lives of the assets, which range from 3 to 10 years for equipment, furniture and building improvements, and from 40 to 50 years for premises, which are depreciated based upon their estimated useful life at the acquisition date. Leasehold improvements are depreciated using the straight-line method over the lesser of the remaining term of the leased facility, or the economic life of the improvement, and ranges from 5 to 10 years. We maintain operating leases worldwide for facilities and equipment. Rent expense for facility leases is recognized ratably over the lease term, and includes adjustments for rent concessions, rent escalations and leasehold improvement allowances. We recognize lease restoration obligations at the fair value of the restoration liabilities when incurred and amortize the restoration assets over the lease term.
Software Development Costs	Certain costs associated with the acquisition or development of internal-use software are also capitalized and recorded in Premises and equipment. Once the software is ready for its intended use, these costs are amortized on a straight-line basis over the software’s estimated useful life, generally 5 years. We review these assets for impairment using the same impairment methodology used for our intangible assets.
Card Member and Other Receivables and Loans	Card Member and Other Loans Card Member loans are recorded at the time a Card Member enters into a point-of-sale transaction with a merchant and represent revolving amounts due on lending card products, as well as amounts due from charge Card Members who utilize the Pay Over Time features on their account and elect to revolve a portion of the outstanding balance by entering into a revolving payment arrangement with us. These loans have a range of terms such as credit limits, interest rates, fees and payment structures, which can be revised over time based on new information about Card Members, and in accordance with applicable regulations and the respective product’s terms and conditions. Card Members holding revolving loans are typically required to make monthly payments based on pre-established amounts and the amounts that Card Members choose to revolve are subject to finance charges. Card Member loans are presented on the Consolidated Balance Sheets net of reserves for losses (refer to Note 4), and include principal and any related accrued interest and fees. Our policy generally is to cease accruing interest on a Card Member loan at the time the account is written off, and establish reserves for interest that we believe will not be collected. Card Member and Other Receivables Card Member receivables are also recorded at the time a Card Member enters into a point-of-sale transaction with a merchant and represent amounts due on charge card products. Each charge card transaction is authorized based on its likely economics, a Card Member’s most recent credit information and spend patterns. Additionally, global spend limits are established to limit our maximum exposure. Charge Card Members generally must pay the full amount billed each month. Card Member receivable balances are presented on the Consolidated Balance Sheets net of reserves for losses (refer to Note 4), and include principal and any related accrued fees. Impaired Card Member Loans and Receivables We consider impaired loans and receivables to include: (i) loans over 90 days past due still accruing interest, (ii) nonaccrual loans and (iii) loans and receivables modified as troubled debt restructurings (TDRs). Reserves for Card Member loans and receivables modified as TDRs are determined as the difference between the cash flows expected to be received from the Card Member (taking into consideration the probability of subsequent defaults), discounted at the original effective interest rates, and the carrying value of the related Card Member loan or receivables balance. We determine the original effective interest rate as the interest rate in effect prior to the imposition of any penalty interest rate. All changes in the impairment measurement are included in Provisions for losses in the Consolidated Statements of Income.
Reserves for Losses	Reserves for losses are primarily based upon statistical and analytical models that analyze portfolio performance and reflect management’s judgment regarding the quantitative components of the reserve. The models take into account several factors, including delinquency-based loss migration rates, loss emergence periods and average losses and recoveries over an appropriate historical period. Management considers whether to adjust the quantitative reserves for certain external and internal qualitative factors, which may increase or decrease the reserves for losses on Card Member loans and receivables. These external factors include employment, spend, sentiment, housing and credit, and changes in the legal and regulatory environment, while the internal factors include increased risk in certain portfolios, impact of risk management initiatives, changes in underwriting requirements and overall process stability. As part of this evaluation process, management also considers various reserve coverage metrics, such as reserves as a percentage of past due amounts, reserves as a percentage of Card Member loans or receivables, and net write-off coverage ratios. Card Member loans and receivables balances are written off when management considers amounts to be uncollectible, which is generally determined by the number of days past due and is typically no later than 180 days past due. Card Member loans and receivables in bankruptcy or owed by deceased individuals are generally written off upon notification.
Investment Securities	Investment securities principally include available-for-sale debt securities carried at fair value on the Consolidated Balance Sheets, with unrealized gains and losses recorded in AOCI, net of income taxes. Realized gains and losses are recognized upon disposition of the securities using the specific identification method. Investment securities also include equity securities carried at fair value on the Consolidated Balance Sheets. Effective January 1, 2018, the unrealized gains and losses on equity securities are recorded in the Consolidated Statements of Income; prior to January 1, 2018, the unrealized gains and losses on equity securities were recorded in AOCI, net of income taxes.
Asset Securitizations	We periodically securitize Card Member loans and receivables arising from our card businesses through the transfer of those assets to securitization trusts, American Express Credit Account Master Trust (the Lending Trust) and American Express Issuance Trust II (the Charge Trust and together with the Lending Trust, the Trusts). The Trusts then issue debt securities collateralized by the transferred assets to third-party investors. The Trusts are considered VIEs as they have insufficient equity at risk to finance their activities, which are to issue debt securities that are collateralized by the underlying Card Member loans and receivables. Refer to Note 1 for further details on the principles of consolidation. We perform the servicing and key decision making for the Trusts, and therefore have the power to direct the activities that most significantly impact the Trusts’ economic performance, which are the collection of the underlying Card Member loans and receivables. In addition, we hold all of the variable interests in both Trusts, with the exception of the debt securities issued to third-party investors. These variable interests held by us provide us with the right to receive benefits and the obligation to absorb losses, which could be significant to both the Lending Trust and the Charge Trust. Based on these considerations, we are the primary beneficiary of the Trusts and therefore consolidate the Trusts. The debt securities issued by the Trusts are non-recourse to us. The securitized Card Member loans and receivables held by the Lending Trust and the Charge Trust, respectively, are available only for payment of the debt securities or other obligations issued or arising in the securitization transactions (refer to Note 3). The long-term debt of each Trust is payable only out of collections on their respective underlying securitized assets (refer to Note 9).
Goodwill and Intangible Assets	Goodwill Goodwill represents the excess of acquisition cost of an acquired business over the fair value of assets acquired and liabilities assumed. We allocate goodwill to our reporting units for the purpose of impairment testing. A reporting unit is defined as an operating segment, or a business that is one level below an operating segment, for which discrete financial information is regularly reviewed by the operating segment manager. We evaluate goodwill for impairment annually as of June 30, or more frequently if events occur or circumstances change that would more likely than not reduce the fair value of one or more of our reporting units below its carrying value. Prior to completing the assessment of goodwill for impairment, we also perform a recoverability test of certain long-lived assets. We have the option to perform a qualitative assessment of goodwill impairment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Alternatively, we can perform a more detailed quantitative assessment of goodwill impairment. This qualitative assessment entails the evaluation of factors such as economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting unit and other company and reporting unit-specific events. If we determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, we then perform the impairment evaluation using the quantitative assessment. Under the quantitative assessment, the first step identifies whether there is a potential impairment by comparing the fair value of a reporting unit to the carrying amount, including goodwill. If the carrying amount of a reporting unit exceeds the fair value, then a test is performed to determine the implied fair value of goodwill. An impairment loss is recognized based on the amount that the carrying amount of goodwill exceeds the implied fair value. When measuring the fair value of our reporting units in the quantitative assessment, we use widely accepted valuation techniques, applying a combination of the income approach (discounted cash flows) and market approach (market multiples). When preparing discounted cash flow models under the income approach, we use internal forecasts to estimate future cash flows expected to be generated by the reporting units. To discount these cash flows, we use the expected cost of equity, determined by using a capital asset pricing model. We believe the discount rates used appropriately reflect the risks and uncertainties in the financial markets generally and specifically in our internally-developed forecasts. When using market multiples under the market approach, we apply comparable publicly traded companies’ multiples (e.g., earnings or revenues) to our reporting units’ actual results. For the years ended December 31, 2018 and 2017, we performed a qualitative assessment in connection with our annual goodwill impairment evaluation and determined that it was more likely than not that the fair values of our reporting units exceeded their carrying values. Other Intangible Assets Intangible assets are amortized on a straight-line basis over their estimated useful lives of 1 to 22 years. We review long-lived assets and asset groups, including intangible assets, for impairment whenever events and circumstances indicate their carrying amounts may not be recoverable. An impairment is recognized if the carrying amount is not recoverable and exceeds the asset or asset group’s fair value.
Other Assets	We account for our tax credit investments, including Qualified Affordable Housing (QAH) investments, using the equity method of accounting.
Membership Rewards	Membership Rewards The Membership Rewards program allows enrolled Card Members to earn points that can be redeemed for a broad range of rewards including travel, shopping, gift cards, and covering eligible charges. We record a balance sheet liability that represents management’s best estimate of the cost of points earned that are expected to be redeemed in the future. The weighted average cost (WAC) per point and the Ultimate Redemption Rate (URR) are key assumptions used to estimate the Membership Rewards liability. We use statistical and actuarial models to estimate the URR based on redemption trends, card product type, enrollment tenure, card spend levels and credit attributes. The expense for Membership Rewards points is included in Card Member rewards expense. We periodically evaluate our liability estimation process and assumptions based on developments in redemption patterns, cost per point redeemed, partner contract changes and other factors.
Stock-based Compensation	We recognize the cost of employee stock awards granted in exchange for employee services based on the grant-date fair value of the award, net of expected forfeitures. Those costs are recognized ratably over the vesting period. Effective January 1, 2017, we adopted new accounting guidance for employee share-based payments and accordingly, income tax benefits related to stock option exercises were recognized in our Consolidated Statements of Income RSAs/RSUs are valued based on the stock price on the date of grant and contain either a) service conditions or b) both service and performance conditions. Certain employees are awarded PGs and other incentive awards that can be settled with cash or equity shares at our discretion, and final Compensation and Benefits Committee payout approval. These awards earn value based on performance, market and/or service conditions, and vest over periods of one to three years. PGs and other incentive awards are generally settled with cash and thus are classified as liabilities; therefore, the fair value is determined at the date of grant and remeasured quarterly as part of compensation expense over the vesting period.
Retirement Plans	We recognize the funded status of our defined benefit pension plans and other postretirement benefit plans, measured as the difference between the fair value of the plan assets and the projected benefit obligation, in the Consolidated Balance Sheets.
Legal Contingencies	We have accrued for certain of our outstanding legal proceedings. An accrual is recorded when it is both (a) probable that a loss has occurred and (b) the amount of loss can be reasonably estimated. There may be instances in which an exposure to loss exceeds the accrual. We evaluate, on a quarterly basis, developments in legal proceedings that could cause an increase or decrease in the amount of the accrual that has been previously recorded, or a revision to the disclosed estimated range of possible losses, as applicable.
Derivatives Financial Instruments and Hedging Activities	We use derivative financial instruments to manage exposures to various market risks. These instruments derive their value from an underlying variable or multiple variables, including interest rates, foreign exchange rates, and an equity index or price, and are carried at fair value on the Consolidated Balance Sheets. Our derivatives are carried at fair value on the Consolidated Balance Sheets. The accounting for changes in fair value depends on the instruments’ intended use and the resulting hedge designation, if any, as discussed below. We formally assess, at inception of the hedge accounting relationship and on a quarterly basis, whether derivatives designated as hedges are highly effective in offsetting the fair value or cash flows of the hedged items. These assessments usually are made through the application of a regression analysis method. If it is determined that a derivative is not highly effective as a hedge, we will discontinue the application of hedge accounting. Gains or losses on the fair value hedging instrument principally offset the losses or gains on the hedged item attributable to the hedged risk. We adopted new accounting guidance providing targeted improvements to the accounting for hedging activities effective January 1, 2018. In compliance with the standard, amounts previously recorded in Other expenses have been prospectively recorded in Total interest expense. We primarily designate foreign currency derivatives, typically foreign exchange forwards, and on occasion foreign currency denominated debt, as hedges of net investments in certain foreign operations. We have derivatives that act as economic hedges, but are not designated as such for hedge accounting purposes. Foreign currency transactions from time to time may be partially or fully economically hedged through foreign currency contracts, primarily foreign exchange forwards. These hedges generally mature within one year. Foreign currency contracts involve the purchase and sale of designated currencies at an agreed upon rate for settlement on a specified date. We also have certain operating agreements containing payments that may be linked to a market rate or price, primarily foreign currency rates. The payment components of these agreements may meet the definition of an embedded derivative, in which case the embedded derivative is accounted for separately and is classified as a foreign exchange contract based on its primary risk exposure. The changes in the fair value of derivatives that are not designated as hedges are intended to offset the related foreign exchange gains or losses of the underlying foreign currency exposures.
Fair Value Measurements	We monitor the market conditions and evaluate the fair value hierarchy levels at least quarterly.
Guarantees	Our recognition of these instruments is at fair value. In addition, we establish reserves when a loss is probable and the amount can be reasonably estimated.
Income Tax Uncertainties	The amount of benefit recognized for financial reporting purposes is based on management’s best judgment of the largest amount of benefit that is more likely than not to be realized on ultimate settlement with the taxing authority given the facts, circumstances and information available at the reporting date. We adjust the level of unrecognized tax benefits when there is new information available to assess the likelihood of the outcome.
Income Taxes	The Tax Act, enacted by the U.S. government on December 22, 2017, made broad and complex changes to the U.S. tax code which required time to interpret. The SEC issued Staff Accounting Bulletin No. 118 (SAB 118) in December, 2017, to provide guidance on accounting for the effects of the Tax Act. SAB 118 provides for a measurement period of up to one year from the Tax Act enactment date for companies to complete their assessment of and accounting for those effects of the Tax Act required under ASC 740 “Implementation Guidance on Accounting for Uncertainty in Income Taxes” to be reported in the period of enactment. Under SAB 118, a company must first reflect the income tax effects of the Tax Act for which the accounting is complete in the period of the date of enactment. To the extent the accounting for other income tax effects is incomplete, but a reasonable estimate can be determined, companies must record a provisional estimate to be included in their financial statements. For any income tax effect for which a reasonable estimate cannot be determined, an entity must continue to apply ASC 740 based on the provisions of the tax laws in effect immediately prior to the Tax Act being enacted until such time as a reasonable estimate can be determined. We record a deferred income tax (benefit) provision when there are differences between assets and liabilities measured for financial reporting and for income tax return purposes. These temporary differences result in taxable or deductible amounts in future years and are measured using the tax rates and laws that will be in effect when such differences are expected to reverse. In particular, the 2017 balances were reduced to reflect the remeasurement of certain federal net deferred tax assets due to the enacted lower federal tax rate of 21 percent. A valuation allowance is established when management determines that it is more likely than not that all or some portion of the benefit of the deferred tax assets will not be realized. The valuation allowances as of December 31, 2018 and 2017 are associated with net operating losses and other deferred tax assets in certain non-U.S. operations. Interest and penalties relating to unrecognized tax benefits are reported in the income tax provision.
Regulatory Matters And Capital Adequacy [Policy Text Block]	Restricted Net Assets of Subsidiaries Certain of our subsidiaries are subject to restrictions on the transfer of net assets under debt agreements and regulatory requirements. These restrictions have not had any effect on our shareholder dividend policy and management does not anticipate any impact in the future. Procedures exist to transfer net assets between the Company and its subsidiaries, while ensuring compliance with the various contractual and regulatory constraints. Bank Holding Company Dividend Restrictions We are limited in our ability to pay dividends by the Federal Reserve, which could prohibit a dividend that would be considered an unsafe or unsound banking practice. It is the policy of the Federal Reserve that bank holding companies generally should pay dividends on preferred and common stock only out of net income available to common shareholders generated over the past year, and only if prospective earnings retention is consistent with the organization’s current and expected future capital needs, asset quality and overall financial condition. Moreover, bank holding companies are required by statute to be a source of strength to their insured depository institution subsidiaries and should not maintain dividend levels that undermine their ability to do so. On an annual basis, we are required to develop and maintain a capital plan, which includes planned dividends over a two-year horizon. We may be limited in our ability to pay dividends if the Federal Reserve objects to our capital plan. Bank Dividend Restrictions AENB is limited in its ability to pay dividends by banking statutes, regulations and supervisory policy. In general, applicable federal and state banking laws prohibit, without first obtaining regulatory approval, insured depository institutions, such as AENB, from making dividend distributions if such distributions are not paid out of available retained earnings or would cause the institution to fail to meet capital adequacy standards. AENB must maintain a capital conservation buffer (and countercyclical buffer if in effect). If AENB’s risk-based capital ratios do not satisfy minimum requirements plus the combined capital conservation buffer (and the countercyclical capital buffer, if applicable), it will face graduated constraints on dividends and other capital distributions based on the amount of the shortfall. In determining the dividends to pay its parent, AENB must also consider the effects on applicable risk-based capital and leverage ratio requirements, as well as policy statements of the federal regulatory agencies. In addition, AENB’s banking regulators have authority to limit or prohibit the payment of a dividend by AENB under a number of circumstances, including if, in the banking regulator’s opinion, payment of a dividend would constitute an unsafe or unsound banking practice in light of the financial condition of the banking organization.
Segment Reporting	We consider a combination of factors when evaluating the composition of our reportable operating segments, including the results reviewed by the chief operating decision maker, economic characteristics, products and services offered, classes of customers, product distribution channels, geographic considerations (primarily United States versus outside the United States), and regulatory environment considerations. Total Revenues Net of Interest Expense We allocate discount revenue and certain other revenues among segments using a transfer pricing methodology. Within the GCSG and GCS segments, discount revenue generally reflects the issuer component of the overall discount revenue generated by each segment’s Card Members; within the GMNS segment, discount revenue generally reflects the network and acquirer component of the overall discount revenue. Net card fees and other fees and commissions are directly attributable to the segment in which they are reported. Interest and fees on loans and certain investment income is directly attributable to the segment in which it is reported. Interest expense represents an allocated funding cost based on a combination of segment funding requirements and internal funding rates. Provisions for Losses The provisions for losses are directly attributable to the segment in which they are reported. Expenses Marketing and business development expense is included in each segment based on the actual expenses incurred. Global brand advertising is primarily reflected in Corporate & Other and may be allocated to the segments based on the actual expense incurred. Rewards and Card Member services expenses are included in each segment based on the actual expenses incurred within the segment. Salaries and employee benefits and other operating expenses reflect expenses such as professional services, occupancy and equipment and communications incurred directly within each segment. In addition, expenses related to support services, such as technology costs, are allocated to each segment primarily based on support service activities directly attributable to the segment. Certain other overhead expenses are allocated from Corporate & Other to the segments based on the relative levels of revenue and Card Member loans and receivables. Income Taxes An income tax provision (benefit) is allocated to each reportable operating segment based on the effective tax rates applicable to various businesses that comprise the segment.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Description of new accounting pronouncements adopted

Effective January 1, 2018, we adopted new revenue recognition guidance issued by the FASB related to contracts with customers. The scope of the new guidance excludes financial instruments such as credit and charge card arrangements. We elected to adopt the standard using the full retrospective method, which we believe is most useful to our investors. Under the full retrospective method, we are applying the standard back to January 1, 2016. As shown below, the most significant impacts of adoption are changes to the classification of certain revenues and expenses, including certain credit and charge card related costs previously netted against discount revenue, such as Card Member cash-back reward costs and statement credits, corporate incentive payments, as well as payments to third-party GNS card issuing partners. Under the new revenue standard, these costs are not considered components of the transaction price of our card acceptance agreements with merchants and thus are not netted against discount revenue, but instead are recognized as expenses. Our payments to third-party GNS card issuing partners are presented net of related revenues earned from the partners.

The adoption of the new guidance also resulted in changes to the recognition timing of certain revenues, the impact of which is not material to net income. Similarly, the adoption did not have a material impact on our financial position or cash flows. We had no material contract assets, contract liabilities or deferred contract costs recorded on the Consolidated Balance Sheet as of December 31, 2018 and 2017. Contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. In adopting the guidance, we implemented changes to our accounting policies, business processes, systems and internal controls to support the recognition, measurement and disclosure requirements under the new standard. Such changes were not material.

In January 2016, the FASB issued new accounting guidance on the recognition and measurement of financial assets and financial liabilities, which was effective and adopted by us as of January 1, 2018. The guidance makes targeted changes to GAAP; specifically to the classification and measurement of equity securities, and to certain disclosure requirements associated with the fair value of financial assets and liabilities. This applies to investments we make in non-public companies in the ordinary course of business, which historically were recognized under the cost method of accounting. These investments will be prospectively adjusted through earnings for observable price changes upon the identification of identical or similar transactions of the same company. The adoption of the guidance did not have a material impact on our financial position, results of operations and cash flows. We implemented changes to our accounting policies, business processes and internal controls in support of the new guidance. Such changes were not material.

In August 2017, the FASB issued new accounting guidance providing targeted improvements to the accounting for hedging activities, effective January 1, 2019, with early adoption permitted in any interim period or fiscal year before the effective date. The guidance introduces a number of amendments, several of which are optional, that are designed to simplify the application of hedge accounting, improve financial statement transparency and more closely align hedge accounting with an entity’s risk management strategies. Effective January 1, 2018, we adopted the guidance, with no material impact on our financial position, results of operations and cash flows, along with associated changes to our accounting policies, business processes and internal controls in support of the new guidance. Such changes were not material.

Principles of Consolidation

The Consolidated Financial Statements are prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Significant intercompany transactions are eliminated.

We consolidate entities in which we hold a “controlling financial interest.” For voting interest entities, we are considered to hold a controlling financial interest when we are able to exercise control over the investees’ operating and financial decisions. For variable interest entities (VIEs), the determination of which is based on the amount and characteristics of the entity’s equity, we are considered to hold a controlling financial interest when we are determined to be the primary beneficiary. A primary beneficiary is the party that has both: (1) the power to direct the activities that most significantly impact that VIE’s economic performance, and (2) the obligation to absorb the losses of, or the right to receive the benefits from, the VIE that could potentially be significant to that VIE.

Entities in which our voting interest in common equity does not provide it with control, but allows us to exert significant influence over operating and financial decisions, are accounted for under the equity method. We also have investments in equity securities where our voting interest is below the level of significant influence, including investments that we make in non-public companies in the ordinary course of business. Such investments are initially recorded at cost and adjusted to fair value through earnings for observable price changes in orderly transactions for identical or similar transactions of the same company or if they are determined to be impaired. See Note 5 for the accounting policy for our marketable equity securities.

Foreign Currency

Monetary assets and liabilities denominated in foreign currencies are translated into U.S. dollars based upon exchange rates prevailing at the end of the reporting period; non-monetary assets and liabilities are translated at the historic exchange rate at the date of the transaction; revenues and expenses are translated at the average month-end exchange rates during the year. Resulting translation adjustments, along with any related qualifying hedge and tax effects, are included in accumulated other comprehensive income (loss) (AOCI), a component of shareholders’ equity. Translation adjustments, including qualifying hedge and tax effects, are reclassified to earnings upon the sale or substantial liquidation of investments in foreign operations. Gains and losses related to transactions in a currency other than the functional currency are reported net in Other expenses, in our Consolidated Statements of Income.

Amounts Based on Estimates and Assumptions

Accounting estimates are an integral part of the Consolidated Financial Statements. These estimates are based, in part, on management’s assumptions concerning future events. Among the more significant assumptions are those that relate to reserves for Card Member losses on loans and receivables, Membership Rewards liability, goodwill and income taxes. These accounting estimates reflect the best judgment of management, but actual results could differ.

Total Revenues Net of Interest Expense

Discount Revenue

Discount revenue primarily represents the amount we earn on transactions occurring at merchants that have entered into a card acceptance agreement with us, or a Global Network Services (GNS) partner or other third-party merchant acquirer, for facilitating transactions between the merchants and Card Members. The amount of fees charged for accepting our cards as payment for goods or services, or merchant discount, varies with, among other factors, the industry in which the merchant conducts business, the merchant’s overall American Express-related transaction volume, the method of payment, the settlement terms with the merchant, the method of submission of transactions and, in certain instances, the geographic scope of the card acceptance agreement between the merchant and us (e.g., local or global) and the transaction amount. The merchant discount is generally deducted from the payment to the merchant and recorded as discount revenue at the time the Card Member transaction occurs.

The card acceptance agreements, which include the agreed-upon terms for charging the merchant discount fee, vary in duration. Our contracts with small- and medium-sized merchants generally have no fixed contractual duration, while those with large merchants are generally for fixed periods, which typically range from three to seven years in duration. Our fixed-period agreements may include auto-renewal features, which may allow the existing terms to continue beyond the stated expiration date until a new agreement is reached. We satisfy our obligations under these agreements over the contract term, often on a daily basis, including through the processing of Card Member transactions and the availability of our payment network.

In cases where the merchant acquirer is a third party (which is the case, for example, under our OptBlue program, or with certain of our GNS partners), we receive a network rate fee in our settlement with the merchant acquirer, which is individually negotiated between us and that merchant acquirer and is recorded as discount revenue at the time the Card Member transaction occurs. In our role as the operator of the American Express network, we also settle with merchants on behalf of our GNS card issuing partners, who in turn receive an issuer rate that is individually negotiated between that issuer and us and is recorded as expense in Marketing and business development (see below) or as contra-revenue in Other revenue.

Net Card Fees

Net card fees represent revenue earned from annual card membership fees, which vary based on the type of card and the number of cards for each account. These fees, net of acquisition costs and a reserve for projected refunds for Card Member cancellations, are deferred and recognized on a straight-line basis over the twelve-month card membership period as Net card fees in the Consolidated Statements of Income. The unamortized net card fee balance is reported in Other liabilities on the Consolidated Balance Sheets (refer to Note 10).

Other Fees and Commissions

Other fees and commissions includes certain fees charged to Card Members, including delinquency fees and foreign currency conversion fees, which are primarily recognized in the period in which they are charged to the Card Member. Other fees and commissions also includes Membership Rewards program fees, which are deferred and recognized over the period covered by the fee, typically one year, the unamortized portion of which is included in Other liabilities on the Consolidated Balance Sheets. In addition, Other fees and commissions includes loyalty coalition-related fees, travel commissions and fees and service fees earned from merchants, that are recognized when the service is performed, which is generally in the period the fee is charged. Refer to Note 19 for additional information.

Contra-revenue

Payments made pursuant to contractual arrangements with our merchants, GNS partners, and other customers are classified as contra-revenue, except where we receive goods, services or other benefits for which the fair value is determinable and measurable, in which case they are recorded as expense.

Interest Income

Interest on Card Member loans is assessed using the average daily balance method. Unless the loan is classified as non-accrual, interest is recognized based upon the principal amount outstanding, in accordance with the terms of the applicable account agreement, until the outstanding balance is paid, or written off.

Interest and dividends on investment securities primarily relate to our performing fixed-income securities. Interest income is recognized as earned using the effective interest method, which adjusts the yield for security premiums and discounts, fees and other payments, so that a constant rate of return is recognized on the investment security’s outstanding balance. Amounts are recognized until securities are in default or when it becomes likely that future interest payments will not be made as scheduled.

Interest on deposits with banks and other is recognized as earned, and primarily relates to the placement of cash, in excess of near-term funding requirements, in interest-bearing time deposits, overnight sweep accounts, and other interest-bearing demand and call accounts.

Interest Expense

Interest expense includes interest incurred primarily to fund Card Member loans and receivables, general corporate purposes and liquidity needs, and is recognized as incurred. Interest expense is divided principally into two categories: (i) deposits, which primarily relates to interest expense on deposits taken from customers and institutions, and (ii) debt, which primarily relates to interest expense on our long-term debt and short-term borrowings, as well as the realized impact of derivatives used to hedge interest rate risk on our long-term debt.

Expenses

Marketing and Business Development

As further described below under “Recently Adopted Accounting Standards,” effective January 1, 2018, in conjunction with the adoption of the new revenue recognition standard, the previously disclosed “Marketing and promotion” line on the Consolidated Statements of Income was changed to “Marketing and business development” to reflect the inclusion of certain reclassified costs from contra-discount revenue and Other expenses. Marketing and business development provides a more comprehensive view of costs related to building and growing our business, including the reclassified costs.

Marketing and business development expense includes costs incurred in the development and initial placement of advertising, which are expensed in the year in which the advertising first takes place. Also included in Marketing and business development expense are Card Member statement credits for qualifying charges on eligible card accounts, corporate incentive payments earned on achievement of preset targets, and certain payments to GNS card issuing partners. These costs are generally expensed as incurred.

Card Member Rewards

We issue charge and credit cards that allow Card Members to participate in various rewards programs (e.g., Membership Rewards, cobrand and cash back). Rewards expense is recognized in the period Card Members earn rewards, generally by spending on their enrolled card products. We record a Card Member rewards liability that represents the estimated cost of points earned that are expected to be redeemed. Pursuant to cobrand agreements, we make payments to our cobrand partners based primarily on the amount of Card Member spending and corresponding rewards earned on such spending and, under certain arrangements, on the number of accounts acquired and retained. The partner is then liable for providing rewards to the Card Member under the cobrand partner’s own loyalty program. Card Member rewards liabilities are impacted over time by enrollment levels, attrition, the volume of points earned and redeemed, and the associated redemption costs. Changes in the Card Member rewards liabilities during the period are taken as an increase or decrease to the Card Member rewards expense in the Consolidated Statement of Income.

Effective January 1, 2018, in conjunction with the adoption of the new revenue recognition standard, Card Member rewards also includes cash-back rewards, which were reclassified from contra discount revenue.

Cash and Cash Equivalents

Cash and cash equivalents include cash and amounts due from banks, interest-bearing bank balances, including securities purchased under resale agreements, and other highly liquid investments with original maturities of 90 days or less.

Premises and Equipment

Premises and equipment, including leasehold improvements, are carried at cost less accumulated depreciation. Costs incurred during construction are capitalized and are depreciated once an asset is placed in service. Depreciation is generally computed using the straight-line method over the estimated useful lives of the assets, which range from 3 to 10 years for equipment, furniture and building improvements, and from 40 to 50 years for premises, which are depreciated based upon their estimated useful life at the acquisition date.

Leasehold improvements are depreciated using the straight-line method over the lesser of the remaining term of the leased facility, or the economic life of the improvement, and ranges from 5 to 10 years. We maintain operating leases worldwide for facilities and equipment. Rent expense for facility leases is recognized ratably over the lease term, and includes adjustments for rent concessions, rent escalations and leasehold improvement allowances. We recognize lease restoration obligations at the fair value of the restoration liabilities when incurred and amortize the restoration assets over the lease term.

Software Development Costs

Certain costs associated with the acquisition or development of internal-use software are also capitalized and recorded in Premises and equipment. Once the software is ready for its intended use, these costs are amortized on a straight-line basis over the software’s estimated useful life, generally 5 years. We review these assets for impairment using the same impairment methodology used for our intangible assets.

Card Member and Other Receivables and Loans

Card Member and Other Loans

Card Member loans are recorded at the time a Card Member enters into a point-of-sale transaction with a merchant and represent revolving amounts due on lending card products, as well as amounts due from charge Card Members who utilize the Pay Over Time features on their account and elect to revolve a portion of the outstanding balance by entering into a revolving payment arrangement with us. These loans have a range of terms such as credit limits, interest rates, fees and payment structures, which can be revised over time based on new information about Card Members, and in accordance with applicable regulations and the respective product’s terms and conditions. Card Members holding revolving loans are typically required to make monthly payments based on pre-established amounts and the amounts that Card Members choose to revolve are subject to finance charges.

Card Member loans are presented on the Consolidated Balance Sheets net of reserves for losses (refer to Note 4), and include principal and any related accrued interest and fees. Our policy generally is to cease accruing interest on a Card Member loan at the time the account is written off, and establish reserves for interest that we believe will not be collected.

Card Member and Other Receivables

Card Member receivables are also recorded at the time a Card Member enters into a point-of-sale transaction with a merchant and represent amounts due on charge card products. Each charge card transaction is authorized based on its likely economics, a Card Member’s most recent credit information and spend patterns. Additionally, global spend limits are established to limit our maximum exposure.

Charge Card Members generally must pay the full amount billed each month. Card Member receivable balances are presented on the Consolidated Balance Sheets net of reserves for losses (refer to Note 4), and include principal and any related accrued fees.

Impaired Card Member Loans and Receivables

We consider impaired loans and receivables to include: (i) loans over 90 days past due still accruing interest, (ii) nonaccrual loans and (iii) loans and receivables modified as troubled debt restructurings (TDRs).

Reserves for Card Member loans and receivables modified as TDRs are determined as the difference between the cash flows expected to be received from the Card Member (taking into consideration the probability of subsequent defaults), discounted at the original effective interest rates, and the carrying value of the related Card Member loan or receivables balance. We determine the original effective interest rate as the interest rate in effect prior to the imposition of any penalty interest rate. All changes in the impairment measurement are included in Provisions for losses in the Consolidated Statements of Income.

Reserves for Losses

Reserves for losses are primarily based upon statistical and analytical models that analyze portfolio performance and reflect management’s judgment regarding the quantitative components of the reserve. The models take into account several factors, including delinquency-based loss migration rates, loss emergence periods and average losses and recoveries over an appropriate historical period. Management considers whether to adjust the quantitative reserves for certain external and internal qualitative factors, which may increase or decrease the reserves for losses on Card Member loans and receivables. These external factors include employment, spend, sentiment, housing and credit, and changes in the legal and regulatory environment, while the internal factors include increased risk in certain portfolios, impact of risk management initiatives, changes in underwriting requirements and overall process stability. As part of this evaluation process, management also considers various reserve coverage metrics, such as reserves as a percentage of past due amounts, reserves as a percentage of Card Member loans or receivables, and net write-off coverage ratios.

Card Member loans and receivables balances are written off when management considers amounts to be uncollectible, which is generally determined by the number of days past due and is typically no later than 180 days past due. Card Member loans and receivables in bankruptcy or owed by deceased individuals are generally written off upon notification.

Investment Securities

Investment securities principally include available-for-sale debt securities carried at fair value on the Consolidated Balance Sheets, with unrealized gains and losses recorded in AOCI, net of income taxes. Realized gains and losses are recognized upon disposition of the securities using the specific identification method.

Investment securities also include equity securities carried at fair value on the Consolidated Balance Sheets. Effective January 1, 2018, the unrealized gains and losses on equity securities are recorded in the Consolidated Statements of Income; prior to January 1, 2018, the unrealized gains and losses on equity securities were recorded in AOCI, net of income taxes.

Asset Securitizations

We periodically securitize Card Member loans and receivables arising from our card businesses through the transfer of those assets to securitization trusts, American Express Credit Account Master Trust (the Lending Trust) and American Express Issuance Trust II (the Charge Trust and together with the Lending Trust, the Trusts). The Trusts then issue debt securities collateralized by the transferred assets to third-party investors.

The Trusts are considered VIEs as they have insufficient equity at risk to finance their activities, which are to issue debt securities that are collateralized by the underlying Card Member loans and receivables. Refer to Note 1 for further details on the principles of consolidation. We perform the servicing and key decision making for the Trusts, and therefore have the power to direct the activities that most significantly impact the Trusts’ economic performance, which are the collection of the underlying Card Member loans and receivables. In addition, we hold all of the variable interests in both Trusts, with the exception of the debt securities issued to third-party investors.

These variable interests held by us provide us with the right to receive benefits and the obligation to absorb losses, which could be significant to both the Lending Trust and the Charge Trust. Based on these considerations, we are the primary beneficiary of the Trusts and therefore consolidate the Trusts.

The debt securities issued by the Trusts are non-recourse to us. The securitized Card Member loans and receivables held by the Lending Trust and the Charge Trust, respectively, are available only for payment of the debt securities or other obligations issued or arising in the securitization transactions (refer to Note 3). The long-term debt of each Trust is payable only out of collections on their respective underlying securitized assets (refer to Note 9).

Goodwill and Intangible Assets

Goodwill

Goodwill represents the excess of acquisition cost of an acquired business over the fair value of assets acquired and liabilities assumed. We allocate goodwill to our reporting units for the purpose of impairment testing. A reporting unit is defined as an operating segment, or a business that is one level below an operating segment, for which discrete financial information is regularly reviewed by the operating segment manager.

We evaluate goodwill for impairment annually as of June 30, or more frequently if events occur or circumstances change that would more likely than not reduce the fair value of one or more of our reporting units below its carrying value. Prior to completing the assessment of goodwill for impairment, we also perform a recoverability test of certain long-lived assets. We have the option to perform a qualitative assessment of goodwill impairment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Alternatively, we can perform a more detailed quantitative assessment of goodwill impairment.

This qualitative assessment entails the evaluation of factors such as economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting unit and other company and reporting unit-specific events. If we determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, we then perform the impairment evaluation using the quantitative assessment.

Under the quantitative assessment, the first step identifies whether there is a potential impairment by comparing the fair value of a reporting unit to the carrying amount, including goodwill. If the carrying amount of a reporting unit exceeds the fair value, then a test is performed to determine the implied fair value of goodwill. An impairment loss is recognized based on the amount that the carrying amount of goodwill exceeds the implied fair value.

When measuring the fair value of our reporting units in the quantitative assessment, we use widely accepted valuation techniques, applying a combination of the income approach (discounted cash flows) and market approach (market multiples). When preparing discounted cash flow models under the income approach, we use internal forecasts to estimate future cash flows expected to be generated by the reporting units. To discount these cash flows, we use the expected cost of equity, determined by using a capital asset pricing model. We believe the discount rates used appropriately reflect the risks and uncertainties in the financial markets generally and specifically in our internally-developed forecasts. When using market multiples under the market approach, we apply comparable publicly traded companies’ multiples (e.g., earnings or revenues) to our reporting units’ actual results.

For the years ended December 31, 2018 and 2017, we performed a qualitative assessment in connection with our annual goodwill impairment evaluation and determined that it was more likely than not that the fair values of our reporting units exceeded their carrying values.

Other Intangible Assets

Intangible assets are amortized on a straight-line basis over their estimated useful lives of 1 to 22 years.

We review long-lived assets and asset groups, including intangible assets, for impairment whenever events and circumstances indicate their carrying amounts may not be recoverable. An impairment is recognized if the carrying amount is not recoverable and exceeds the asset or asset group’s fair value.

Other Assets

We account for our tax credit investments, including Qualified Affordable Housing (QAH) investments, using the equity method of accounting.

Membership Rewards

The Membership Rewards program allows enrolled Card Members to earn points that can be redeemed for a broad range of rewards including travel, shopping, gift cards, and covering eligible charges. We record a balance sheet liability that represents management’s best estimate of the cost of points earned that are expected to be redeemed in the future. The weighted average cost (WAC) per point and the Ultimate Redemption Rate (URR) are key assumptions used to estimate the Membership Rewards liability. We use statistical and actuarial models to estimate the URR based on redemption trends, card product type, enrollment tenure, card spend levels and credit attributes.

The expense for Membership Rewards points is included in Card Member rewards expense. We periodically evaluate our liability estimation process and assumptions based on developments in redemption patterns, cost per point redeemed, partner contract changes and other factors.

Stock-based Compensation

We recognize the cost of employee stock awards granted in exchange for employee services based on the grant-date fair value of the award, net of expected forfeitures. Those costs are recognized ratably over the vesting period.

Effective January 1, 2017, we adopted new accounting guidance for employee share-based payments and accordingly, income tax benefits related to stock option exercises were recognized in our Consolidated Statements of Income

RSAs/RSUs are valued based on the stock price on the date of grant and contain either a) service conditions or b) both service and performance conditions.

Certain employees are awarded PGs and other incentive awards that can be settled with cash or equity shares at our discretion, and final Compensation and Benefits Committee payout approval. These awards earn value based on performance, market and/or service conditions, and vest over periods of one to three years.

PGs and other incentive awards are generally settled with cash and thus are classified as liabilities; therefore, the fair value is determined at the date of grant and remeasured quarterly as part of compensation expense over the vesting period.

Retirement Plans

We recognize the funded status of our defined benefit pension plans and other postretirement benefit plans, measured as the difference between the fair value of the plan assets and the projected benefit obligation, in the Consolidated Balance Sheets.

Legal Contingencies

We have accrued for certain of our outstanding legal proceedings. An accrual is recorded when it is both (a) probable that a loss has occurred and (b) the amount of loss can be reasonably estimated. There may be instances in which an exposure to loss exceeds the accrual. We evaluate, on a quarterly basis, developments in legal proceedings that could cause an increase or decrease in the amount of the accrual that has been previously recorded, or a revision to the disclosed estimated range of possible losses, as applicable.

Derivatives Financial Instruments and Hedging Activities

We use derivative financial instruments to manage exposures to various market risks. These instruments derive their value from an underlying variable or multiple variables, including interest rates, foreign exchange rates, and an equity index or price, and are carried at fair value on the Consolidated Balance Sheets.

Our derivatives are carried at fair value on the Consolidated Balance Sheets. The accounting for changes in fair value depends on the instruments’ intended use and the resulting hedge designation, if any, as discussed below.

We formally assess, at inception of the hedge accounting relationship and on a quarterly basis, whether derivatives designated as hedges are highly effective in offsetting the fair value or cash flows of the hedged items. These assessments usually are made through the application of a regression analysis method. If it is determined that a derivative is not highly effective as a hedge, we will discontinue the application of hedge accounting.

Gains or losses on the fair value hedging instrument principally offset the losses or gains on the hedged item attributable to the hedged risk.

We adopted new accounting guidance providing targeted improvements to the accounting for hedging activities effective January 1, 2018. In compliance with the standard, amounts previously recorded in Other expenses have been prospectively recorded in Total interest expense.

We primarily designate foreign currency derivatives, typically foreign exchange forwards, and on occasion foreign currency denominated debt, as hedges of net investments in certain foreign operations.

We have derivatives that act as economic hedges, but are not designated as such for hedge accounting purposes. Foreign currency transactions from time to time may be partially or fully economically hedged through foreign currency contracts, primarily foreign exchange forwards. These hedges generally mature within one year. Foreign currency contracts involve the purchase and sale of designated currencies at an agreed upon rate for settlement on a specified date.

We also have certain operating agreements containing payments that may be linked to a market rate or price, primarily foreign currency rates. The payment components of these agreements may meet the definition of an embedded derivative, in which case the embedded derivative is accounted for separately and is classified as a foreign exchange contract based on its primary risk exposure.

The changes in the fair value of derivatives that are not designated as hedges are intended to offset the related foreign exchange gains or losses of the underlying foreign currency exposures.

Fair Value Measurements

We monitor the market conditions and evaluate the fair value hierarchy levels at least quarterly.

Guarantees

Our recognition of these instruments is at fair value. In addition, we establish reserves when a loss is probable and the amount can be reasonably estimated.

Income Tax Uncertainties

The amount of benefit recognized for financial reporting purposes is based on management’s best judgment of the largest amount of benefit that is more likely than not to be realized on ultimate settlement with the taxing authority given the facts, circumstances and information available at the reporting date. We adjust the level of unrecognized tax benefits when there is new information available to assess the likelihood of the outcome.

Income Taxes

The Tax Act, enacted by the U.S. government on December 22, 2017, made broad and complex changes to the U.S. tax code which required time to interpret. The SEC issued Staff Accounting Bulletin No. 118 (SAB 118) in December, 2017, to provide guidance on accounting for the effects of the Tax Act. SAB 118 provides for a measurement period of up to one year from the Tax Act enactment date for companies to complete their assessment of and accounting for those effects of the Tax Act required under ASC 740 “Implementation Guidance on Accounting for Uncertainty in Income Taxes” to be reported in the period of enactment. Under SAB 118, a company must first reflect the income tax effects of the Tax Act for which the accounting is complete in the period of the date of enactment. To the extent the accounting for other income tax effects is incomplete, but a reasonable estimate can be determined, companies must record a provisional estimate to be included in their financial statements. For any income tax effect for which a reasonable estimate cannot be determined, an entity must continue to apply ASC 740 based on the provisions of the tax laws in effect immediately prior to the Tax Act being enacted until such time as a reasonable estimate can be determined.

We record a deferred income tax (benefit) provision when there are differences between assets and liabilities measured for financial reporting and for income tax return purposes. These temporary differences result in taxable or deductible amounts in future years and are measured using the tax rates and laws that will be in effect when such differences are expected to reverse. In particular, the 2017 balances were reduced to reflect the remeasurement of certain federal net deferred tax assets due to the enacted lower federal tax rate of 21 percent.

A valuation allowance is established when management determines that it is more likely than not that all or some portion of the benefit of the deferred tax assets will not be realized. The valuation allowances as of December 31, 2018 and 2017 are associated with net operating losses and other deferred tax assets in certain non-U.S. operations.

Interest and penalties relating to unrecognized tax benefits are reported in the income tax provision.

Regulatory Matters And Capital Adequacy [Policy Text Block]

Restricted Net Assets of Subsidiaries

Certain of our subsidiaries are subject to restrictions on the transfer of net assets under debt agreements and regulatory requirements. These restrictions have not had any effect on our shareholder dividend policy and management does not anticipate any impact in the future. Procedures exist to transfer net assets between the Company and its subsidiaries, while ensuring compliance with the various contractual and regulatory constraints.

Bank Holding Company Dividend Restrictions

We are limited in our ability to pay dividends by the Federal Reserve, which could prohibit a dividend that would be considered an unsafe or unsound banking practice. It is the policy of the Federal Reserve that bank holding companies generally should pay dividends on preferred and common stock only out of net income available to common shareholders generated over the past year, and only if prospective earnings retention is consistent with the organization’s current and expected future capital needs, asset quality and overall financial condition. Moreover, bank holding companies are required by statute to be a source of strength to their insured depository institution subsidiaries and should not maintain dividend levels that undermine their ability to do so. On an annual basis, we are required to develop and maintain a capital plan, which includes planned dividends over a two-year horizon. We may be limited in our ability to pay dividends if the Federal Reserve objects to our capital plan.

Bank Dividend Restrictions

AENB is limited in its ability to pay dividends by banking statutes, regulations and supervisory policy. In general, applicable federal and state banking laws prohibit, without first obtaining regulatory approval, insured depository institutions, such as AENB, from making dividend distributions if such distributions are not paid out of available retained earnings or would cause the institution to fail to meet capital adequacy standards. AENB must maintain a capital conservation buffer (and countercyclical buffer if in effect). If AENB’s risk-based capital ratios do not satisfy minimum requirements plus the combined capital conservation buffer (and the countercyclical capital buffer, if applicable), it will face graduated constraints on dividends and other capital distributions based on the amount of the shortfall.

In determining the dividends to pay its parent, AENB must also consider the effects on applicable risk-based capital and leverage ratio requirements, as well as policy statements of the federal regulatory agencies. In addition, AENB’s banking regulators have authority to limit or prohibit the payment of a dividend by AENB under a number of circumstances, including if, in the banking regulator’s opinion, payment of a dividend would constitute an unsafe or unsound banking practice in light of the financial condition of the banking organization.

Segment Reporting

We consider a combination of factors when evaluating the composition of our reportable operating segments, including the results reviewed by the chief operating decision maker, economic characteristics, products and services offered, classes of customers, product distribution channels, geographic considerations (primarily United States versus outside the United States), and regulatory environment considerations.

Total Revenues Net of Interest Expense

We allocate discount revenue and certain other revenues among segments using a transfer pricing methodology. Within the GCSG and GCS segments, discount revenue generally reflects the issuer component of the overall discount revenue generated by each segment’s Card Members; within the GMNS segment, discount revenue generally reflects the network and acquirer component of the overall discount revenue.

Net card fees and other fees and commissions are directly attributable to the segment in which they are reported.

Interest and fees on loans and certain investment income is directly attributable to the segment in which it is reported. Interest expense represents an allocated funding cost based on a combination of segment funding requirements and internal funding rates.

Provisions for Losses

The provisions for losses are directly attributable to the segment in which they are reported.

Expenses

Marketing and business development expense is included in each segment based on the actual expenses incurred. Global brand advertising is primarily reflected in Corporate & Other and may be allocated to the segments based on the actual expense incurred. Rewards and Card Member services expenses are included in each segment based on the actual expenses incurred within the segment.

Salaries and employee benefits and other operating expenses reflect expenses such as professional services, occupancy and equipment and communications incurred directly within each segment. In addition, expenses related to support services, such as technology costs, are allocated to each segment primarily based on support service activities directly attributable to the segment. Certain other overhead expenses are allocated from Corporate & Other to the segments based on the relative levels of revenue and Card Member loans and receivables.

Income Taxes

An income tax provision (benefit) is allocated to each reportable operating segment based on the effective tax rates applicable to various businesses that comprise the segment.