Line of Credit Facilities, Related Party Facility

No definition available.

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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

- Definition

The amount of any current tax-related balances due to affiliates as of the date of each statement of financial position presented.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32809-109319

+ Details

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

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

- Definition

Purchases during the period (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=acf_JuniorSubordinatedRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=acf_GeneralMotorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=acf_ThreeYearRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=acf_FiveYearRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=acf_ThreeHundredandSixtyFourDayRevolvingCreditFacilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=acf_PurchaseofRetailFinanceReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=acf_ThreeYearRevolvingCreditFacilityExpiringApril2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Related Party Transactions - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2020	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Long-term Line of Credit		$ 0
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Tax expense due to related party		6,000,000		$ 4,000,000
Junior Subordinated Revolving Credit Facility [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Line of credit facilities - GM Related party facility		$ 1,000,000,000
Line of Credit [Member]
Related Party Transaction [Line Items]
Debt instrument term		4 years
Line of Credit [Member] \| Revolving Credit Facility [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 14,500,000,000.0
Line of Credit [Member] \| Revolving Credit Facility [Member] \| Three Year Revolving Credit Facility [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 4,000,000,000.0
Debt instrument term		3 years
Long-term Line of Credit			$ 3,400,000,000
Line of Credit [Member] \| Revolving Credit Facility [Member] \| Five Year Revolving Credit Facility [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 10,500,000,000
Debt instrument term		5 years
Line of Credit [Member] \| Revolving Credit Facility [Member] \| Three Hundred and Sixty-Four Day Revolving Credit Facilities [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 2,000,000,000.0
Debt instrument term		364 days
Purchase of Retail Finance Receivables [Member] \| Parent Company [Member]
Related Party Transaction [Line Items]
Related party purchases		$ 219,000,000	$ 194,000,000
Subsequent Event [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| Three Year Revolving Credit Facility [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity	$ 4,000,000,000.0
Debt instrument term	3 years
Subsequent Event [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| Five Year Revolving Credit Facility [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Debt instrument term	5 years
Subsequent Event [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| Three Hundred and Sixty-Four Day Revolving Credit Facilities [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity	$ 2,000,000,000.0
Debt instrument term	364 days
Subsequent Event [Member] \| Line of Credit [Member] \| Revolving Credit Facility [Member] \| Three Year Revolving Credit Facility Expiring April 2022 [Member] \| General Motors [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity	$ 3,600,000,000.0