Reserves (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Changes in the Card Member receivable reserve for losses
Balance, January 1	$ 110	$ 114
Provisions	171	101
Other credits	35	13
Net write-offs	(142)	(105)
Other debits	(16)	(17)
Balance, September 30	$ 158	$ 106

Accounts receivable reserve rollforward

No definition available.

Name:	aexc_AccountsReceivableReserveRollForwardAbstract
Namespace Prefix:	aexc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents adjustments to Card Member receivables reserve attributable to purchases of Card Member receivables & participation interest in Card Member receivables from affiliates.

+ References

No definition available.

+ Details

Name:	aexc_NetAdditionsDeductionsProvisionsForLossesChargeCardOther
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represent reserve for losses attributable to participation interests in Card Member receivables sold to an affiliate.

+ References

No definition available.

+ Details

Name:	aexc_ProvisionsForLossesChargeCardDeductionsOther
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents net write-offs consisting of principal (resulting from authorized transactions), less recoveries, for the period.

+ References

No definition available.

+ Details

Name:	aexc_ProvisionsForLossesDeductionsChargeCardNetWriteOffsPrincipal
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130534-203044

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.5)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130543-203045

+ Details

Name:	us-gaap_ProvisionForDoubtfulAccounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration