Income Taxes 4 (Details) $ in Millions	Dec. 31, 2018 USD ($)
Deemed Repatriation Tax Payments Due By Year [Line Items]
2019	$ 63
2020-2021	116
2022-2023	116
2024 and Thereafter	436
Total	$ 731

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

No definition available.

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

No definition available.

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Data Type:	xbrli:monetaryItemType
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Represents estimated obligation under the tax act to pay deemed repatriation tax on certain non US earnings.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Represents estimated obligation under the tax act to pay deemed repatriation tax on certain non US earnings.

No definition available.

Name:	aexc_Deemedrepatriationtaxpaymentsduebyyear2023andthereaftermember
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
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No definition available.

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

No definition available.

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Data Type:	xbrli:monetaryItemType
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