Derivative Financial Instruments and Hedging Activities - Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Hedged Liability, Statement of Financial Position [Extensible Enumeration]	Unsecured debt (Note 6)	Unsecured debt (Note 6)
Derivatives designated as hedges \| Fair value hedges
Derivatives, Fair Value [Line Items]
Carrying Amount of Hedged Items	$ 29,843	$ 28,319
Cumulative Amount of Fair Value Hedging Adjustments	897	781
Discontinued hedge cumulative amount of fair value hedging adjustments	$ 461	$ 86

Derivative Liability, Fair Value Hedging Adjustment Increase (Decrease)

No definition available.

Name:	acf_DerivativeLiabilityFairValueHedgingAdjustmentIncreaseDecrease
Namespace Prefix:	acf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Derivative Liability, Fair Value Hedging Adjustment Increase (Decrease), Discontinuation Of Hedge Accounting

+ References

No definition available.

+ Details

Name:	acf_DerivativeLiabilityFairValueHedgingAdjustmentIncreaseDecreaseDiscontinuationOfHedgeAccounting
Namespace Prefix:	acf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of liability hedged in fair value hedging relationship.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4EE
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

+ Details

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

- Definition

Indicates line item in statement of financial position that includes hedged liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4EE
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

+ Details

Name:	us-gaap_HedgedLiabilityStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: