Customer Deposits - By Deposit Type (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
U.S. interest-bearing deposits:
Savings accounts	$ 113,998	$ 108,364
Checking accounts	2,755	2,045
Certificates of deposit:
Direct	5,169	4,303
Third-party (brokered)	11,437	8,109
Sweep accounts – Third-party (brokered)	15,566	15,612
Total U.S. interest-bearing deposits	148,924	138,433
Other deposits	88	72
Total customer deposits	149,883	139,413
Card Member Credit Balances
Certificates of deposit:
Card Member credit balances	$ 871	$ 908

Other Interest And Noninterest-Bearing Deposit Liabilities

No definition available.

Name:	axp_OtherInterestAndNoninterestBearingDepositLiabilities
Namespace Prefix:	axp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents third party certificate of deposit accounts offered by the Company's Banks.

+ References

No definition available.

+ Details

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Namespace Prefix:	axp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents third party sweep accounts offered by the Company's Banks.

+ References

No definition available.

+ Details

Name:	axp_ThirdPartySweepAccounts
Namespace Prefix:	axp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of money in accounts that may bear interest and that the depositor is entitled to withdraw at any time without prior notice.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(12))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs).

+ References

+ Details

Name:	us-gaap_DepositsSavingsDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Total amount of interest-bearing domestic deposit liabilities, which may include brokered, retail, demand, checking, notice of withdrawal, money market and other interest-bearing deposits.

+ References

+ Details

Name:	us-gaap_InterestBearingDepositLiabilitiesDomestic
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Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest-bearing domestic certificate of deposit liabilities.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

+ References

+ Details

Name:	us-gaap_NoninterestBearingDepositLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Period Type: