Income Taxes 4 (Details) $ in Millions	Dec. 31, 2020 USD ($)
Income Tax Disclosure [Abstract]
2021	$ 0
2022 - 2023	6
2024 – 2025	254
2026 and thereafter	181
Total	$ 441

Represents estimated obligation under the tax act to pay deemed repatriation tax on certain non US earnings.

No definition available.

Name:	aexc_DeemedRepatriationTaxPaymentsDueByYear2ThroughYear3
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents estimated obligation under the tax act to pay deemed repatriation tax on certain non US earnings.

No definition available.

Name:	aexc_DeemedRepatriationTaxPaymentsDueByYear6AndThereafter
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents estimated obligation under the tax act to pay deemed repatriation tax on certain non US earnings.

No definition available.

Name:	aexc_DeemedRepatriationTaxPaymentsDueByYearDeemedRepatriationTaxPaymentsDueByYear4ThroughYear5
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents estimated obligation under the tax act to pay deemed repatriation tax on certain non US earnings.

No definition available.

Name:	aexc_DeemedRepatriationTaxPaymentsDueInNextTwelveMonths
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents estimated obligation under the tax act to pay deemed repatriation tax on certain non US earnings payable to AXP.

No definition available.

Name:	aexc_Deemedrepatriationtaxpaymentsduebyyeartotalmember
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	us-gaap_IncomeTaxDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration