Basis of Presentation (Policies)	9 Months Ended
Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The preparation of Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosures of contingent assets and liabilities. These accounting estimates reflect the best judgment of management, but actual results could differ. Certain reclassifications of prior period amounts have been made to conform to the current period presentation.
Recently Adopted Accounting Standards	Effective January 1, 2020, we adopted the new credit reserving methodology, applicable to certain financial instruments, known as the Current Expected Credit Loss (CECL) methodology under a modified retrospective transition. The CECL methodology requires measurement of expected credit losses for the estimated life of the financial instrument, not only based on historical experience and current conditions, but also by including reasonable and supportable forecasts incorporating forward-looking information. Upon implementation, total loan reserves increased by $1,663 million and total receivable reserves decreased by $493 million, along with the associated current and deferred tax impact of $288 million, and an offset to the opening balance of retained earnings, net of tax, of $882 million. There were no material changes to our business processes or internal controls as a result of adopting the new guidance. Refer to Note 3 for additional information on how management estimates reserves for credit losses in accordance with the CECL methodology. In addition, for available-for-sale debt securities, the new methodology replaces the other-than-temporary impairment model and requires the recognition of an allowance for reductions in a security’s fair value attributable to declines in credit quality, instead of a direct write-down of the security, when a valuation decline is determined to be other-than-temporary. There was no financial impact related to this implementation. Refer to Note 4 for additional information.
Impaired Loans and Receivables	Impaired Loans and Receivables Impaired loans and receivables are individual larger balance or homogeneous pools of smaller balance loans and receivables for which it is probable that we will be unable to collect all amounts due according to the original contractual terms of the customer agreement. 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). In instances where the customer is experiencing financial difficulty, we may modify, through various financial relief programs, loans and receivables with the intention to minimize losses and improve collectability, while providing customers with temporary or permanent financial relief. We have classified loans and receivables in these modification programs as TDRs and continue to classify customer accounts that have exited a modification program as a TDR, with such accounts identified as “Out of Program TDRs.” Such modifications to the loans and receivables primarily include (i) temporary interest rate reductions (possibly as low as zero percent, in which case the loan is characterized as non-accrual in our TDR disclosures), (ii) placing the customer on a fixed payment plan not to exceed 60 months and (iii) suspending delinquency fees until the customer exits the modification program. Upon entering the modification program, the customer’s ability to make future purchases is either limited, canceled, or in certain cases suspended until the customer successfully exits from the modification program. In accordance with the modification agreement with the customer, loans and/or receivables may revert back to the original contractual terms (including the contractual interest rate where applicable) when the customer exits the modification program, which is (i) when all payments have been made in accordance with the modification agreement or (ii) when the customer defaults out of the modification program. Reserves for modifications deemed TDRs are measured individually and incorporate a discounted cash flow model. All changes in the impairment measurement are included within provisions for credit losses.
Reserves for Credit Losses	Reserves for credit losses represent our best estimate of the expected credit losses in our outstanding portfolio of Card Member loans and receivables as of the balance sheet date. The CECL methodology, which became effective January 1, 2020, requires us to estimate lifetime expected credit losses by incorporating historical loss experience, as well as current and future economic conditions over a reasonable and supportable period (R&S Period) beyond the balance sheet date. We make various judgments combined with historical loss experience to calculate a reserve rate that is applied to the outstanding loan or receivable balance to produce a reserve for expected credit losses. We use a combination of statistically-based models that incorporate current and future economic conditions throughout the R&S Period. The process of estimating expected credit losses is based on several key models: Probability of Default (PD), Exposure at Default (EAD), and future recoveries for each month of the R&S Period. Beyond the R&S Period, we estimate expected credit losses using our historical loss rates. •PD models are used to estimate the likelihood an account will be written-off. •EAD models are used to estimate the balance of an account at the time of write-off. This includes balances less expected repayments based on historical payment and revolve behavior, which vary by customer. Due to the nature of revolving loan portfolios, the EAD models are complex and involve assumptions regarding the relationship between future spend and payment behaviors. •Recovery models are used to estimate amounts that are expected to be received from Card Members after default occurs, typically as a result of collection efforts. Future recoveries are estimated taking into consideration the time of default, time elapsed since default and macroeconomic conditions. We also estimate the likelihood and magnitude of recovery of previously written off accounts considering how long ago the account was written off and future economic conditions. Our models are developed using historical loss experience covering the economic cycle and consider the impact of account characteristics on expected losses. Future economic conditions that are incorporated over the R&S Period include multiple macroeconomic scenarios provided to us by an independent third party. Management reviews these economic scenarios quarterly and uses their judgment to weight them in order to reflect the uncertainty surrounding these scenarios. These macroeconomic scenarios contain certain variables, including unemployment rates and real gross domestic product, that are significant to our models. We also evaluate whether to include qualitative reserves to cover losses that are expected but, in our assessment, may not be adequately represented in the quantitative methods or the economic assumptions. We consider whether to adjust the quantitative reserves (higher or lower) to address possible limitations within the models or factors not included within the models, such as external conditions, emerging portfolio trends, the nature and size of the portfolio, portfolio concentrations, the volume and severity of past due accounts, or management risk actions. Lifetime losses for most of our loans and receivables are evaluated at an appropriate level of granularity, including assessment on a pooled basis where financial assets share similar risk characteristics, such as past spend and remittance behaviors, credit bureau scores where available, delinquency status, tenure of balance outstanding, amongst others. Credit losses on accrued interest are measured and presented as part of Reserves for credit losses on the Consolidated Balance Sheets and within the Provisions for credit losses in the Consolidated Statements of Income, rather than reversing interest income. Separate models are used for accounts deemed a troubled debt restructuring, which are measured individually using a discounted cash flow model. See Note 2 for information on troubled debt restructurings. Loans and receivable balances are written off when we consider 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 for pay in full or revolving loans and 120 days past due for term loans. Loans and receivables in bankruptcy or owed by deceased individuals are generally written off upon notification. Results for reporting periods beginning after January 1, 2020 are presented using the CECL methodology while comparative information continues to be reported in accordance with the incurred loss methodology in effect for prior periods.
Investments	Investment securities principally include available-for-sale debt securities carried at fair value on the Consolidated Balance Sheets. The CECL methodology, which became effective January 1, 2020, requires us to estimate lifetime expected credit losses for all available-for-sale debt securities in an unrealized loss position. Comparative information continues to be reported in accordance with the methodology in effect for prior periods. When estimating a security’s probability of default and the recovery rate, we assess the security’s credit indicators, including credit ratings. If our assessment indicates that an expected credit loss exists, we determine the portion of the unrealized loss attributable to credit deterioration and record an allowance for the expected credit loss through the Consolidated Statements of Income in Other loans Provision for credit losses. Unrealized gains and any portion of a security’s unrealized loss attributable to non-credit losses are recorded in the Consolidated Statements of Comprehensive Income, net of tax. Investment securities also include equity securities carried at fair value on the Consolidated Balance Sheets with unrealized gains and losses recorded in the Consolidated Statements of Income as Other, net expense. Realized gains and losses are recognized upon disposition of the securities using the specific identification method.
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. 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.
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	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 Values	We have certain assets that are subject to measurement at fair value on a nonrecurring basis. For these assets, measurement at fair value in periods subsequent to their initial recognition is applicable if they are determined to be impaired or where there are observable price changes for equity investments without readily determinable fair values.
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.

Basis of Presentation (Policies)

9 Months Ended

Sep. 30, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The preparation of Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosures of contingent assets and liabilities. These accounting estimates reflect the best judgment of management, but actual results could differ.

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

Recently Adopted Accounting Standards

Effective January 1, 2020, we adopted the new credit reserving methodology, applicable to certain financial instruments, known as the Current Expected Credit Loss (CECL) methodology under a modified retrospective transition. The CECL methodology requires measurement of expected credit losses for the estimated life of the financial instrument, not only based on historical experience and current conditions, but also by including reasonable and supportable forecasts incorporating forward-looking information. Upon implementation, total loan reserves increased by $1,663 million and total receivable reserves decreased by $493 million, along with the associated current and deferred tax impact of $288 million, and an offset to the opening balance of retained earnings, net of tax, of $882 million. There were no material changes to our business processes or internal controls as a result of adopting the new guidance. Refer to Note 3 for additional information on how management estimates reserves for credit losses in accordance with the CECL methodology. In addition, for available-for-sale debt securities, the new methodology replaces the other-than-temporary impairment model and requires the recognition of an allowance for reductions in a security’s fair value attributable to declines in credit quality, instead of a direct write-down of the security, when a valuation decline is determined to be other-than-temporary. There was no financial impact related to this implementation. Refer to Note 4 for additional information.

Impaired Loans and Receivables

Impaired loans and receivables are individual larger balance or homogeneous pools of smaller balance loans and receivables for which it is probable that we will be unable to collect all amounts due according to the original contractual terms of the customer agreement. 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).

In instances where the customer is experiencing financial difficulty, we may modify, through various financial relief programs, loans and receivables with the intention to minimize losses and improve collectability, while providing customers with temporary or permanent financial relief. We have classified loans and receivables in these modification programs as TDRs and continue to classify customer accounts that have exited a modification program as a TDR, with such accounts identified as “Out of Program TDRs.”

Such modifications to the loans and receivables primarily include (i) temporary interest rate reductions (possibly as low as zero percent, in which case the loan is characterized as non-accrual in our TDR disclosures), (ii) placing the customer on a fixed payment plan not to exceed 60 months and (iii) suspending delinquency fees until the customer exits the modification program. Upon entering the modification program, the customer’s ability to make future purchases is either limited, canceled, or in certain cases suspended until the customer successfully exits from the modification program. In accordance with the modification agreement with the customer, loans and/or receivables may revert back to the original contractual terms (including the contractual interest rate where applicable) when the customer exits the modification program, which is (i) when all payments have been made in accordance with the modification agreement or (ii) when the customer defaults out of the modification program.

Reserves for modifications deemed TDRs are measured individually and incorporate a discounted cash flow model. All changes in the impairment measurement are included within provisions for credit losses.

Reserves for Credit Losses

Reserves for credit losses represent our best estimate of the expected credit losses in our outstanding portfolio of Card Member loans and receivables as of the balance sheet date. The CECL methodology, which became effective January 1, 2020, requires us to estimate lifetime expected credit losses by incorporating historical loss experience, as well as current and future economic conditions over a reasonable and supportable period (R&S Period) beyond the balance sheet date. We make various judgments combined with historical loss experience to calculate a reserve rate that is applied to the outstanding loan or receivable balance to produce a reserve for expected credit losses.

We use a combination of statistically-based models that incorporate current and future economic conditions throughout the R&S Period. The process of estimating expected credit losses is based on several key models: Probability of Default (PD), Exposure at Default (EAD), and future recoveries for each month of the R&S Period. Beyond the R&S Period, we estimate expected credit losses using our historical loss rates.

•PD models are used to estimate the likelihood an account will be written-off.

•EAD models are used to estimate the balance of an account at the time of write-off. This includes balances less expected repayments based on historical payment and revolve behavior, which vary by customer. Due to the nature of revolving loan portfolios, the EAD models are complex and involve assumptions regarding the relationship between future spend and payment behaviors.

•Recovery models are used to estimate amounts that are expected to be received from Card Members after default occurs, typically as a result of collection efforts. Future recoveries are estimated taking into consideration the time of default, time elapsed since default and macroeconomic conditions.

We also estimate the likelihood and magnitude of recovery of previously written off accounts considering how long ago the account was written off and future economic conditions. Our models are developed using historical loss experience covering the economic cycle and consider the impact of account characteristics on expected losses.

Future economic conditions that are incorporated over the R&S Period include multiple macroeconomic scenarios provided to us by an independent third party. Management reviews these economic scenarios quarterly and uses their judgment to weight them in order to reflect the uncertainty surrounding these scenarios. These macroeconomic scenarios contain certain variables, including unemployment rates and real gross domestic product, that are significant to our models.

We also evaluate whether to include qualitative reserves to cover losses that are expected but, in our assessment, may not be adequately represented in the quantitative methods or the economic assumptions. We consider whether to adjust the quantitative reserves (higher or lower) to address possible limitations within the models or factors not included within the models, such as external conditions, emerging portfolio trends, the nature and size of the portfolio, portfolio concentrations, the volume and severity of past due accounts, or management risk actions.

Lifetime losses for most of our loans and receivables are evaluated at an appropriate level of granularity, including assessment on a pooled basis where financial assets share similar risk characteristics, such as past spend and remittance behaviors, credit bureau scores where available, delinquency status, tenure of balance outstanding, amongst others. Credit losses on accrued interest are measured and presented as part of Reserves for credit losses on the Consolidated Balance Sheets and within the Provisions for credit losses in the Consolidated Statements of Income, rather than reversing interest income. Separate models are used for accounts deemed a troubled debt restructuring, which are measured individually using a discounted cash flow model. See Note 2 for information on troubled debt restructurings.

Loans and receivable balances are written off when we consider 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 for pay in full or revolving loans and 120 days past due for term loans. Loans and receivables in bankruptcy or owed by deceased individuals are generally written off upon notification.

Results for reporting periods beginning after January 1, 2020 are presented using the CECL methodology while comparative information continues to be reported in accordance with the incurred loss methodology in effect for prior periods.

Investments

Investment securities principally include available-for-sale debt securities carried at fair value on the Consolidated Balance Sheets. The CECL methodology, which became effective January 1, 2020, requires us to estimate lifetime expected credit losses for all available-for-sale debt securities in an unrealized loss position. Comparative information continues to be reported in accordance with the methodology in effect for prior periods. When estimating a security’s probability of default and the recovery rate, we assess the security’s credit indicators, including credit ratings. If our assessment indicates that an expected credit loss exists, we determine the portion of the unrealized loss attributable to credit deterioration and record an allowance for the expected credit loss through the Consolidated Statements of Income in Other loans Provision for credit losses. Unrealized gains and any portion of a security’s unrealized loss attributable to non-credit losses are recorded in the Consolidated Statements of Comprehensive Income, net of tax. Investment securities also include equity securities carried at fair value on the Consolidated Balance Sheets with unrealized gains and losses recorded in the Consolidated Statements of Income as Other, net expense. Realized gains and losses are recognized upon disposition of the securities using the specific identification method.

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. 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.

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

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 Values

We have certain assets that are subject to measurement at fair value on a nonrecurring basis. For these assets, measurement at fair value in periods subsequent to their initial recognition is applicable if they are determined to be impaired or where there are observable price changes for equity investments without readily determinable fair values.

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.