Securitization Notes Payable (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2012	Dec. 31, 2011
Debt Instrument, Maturity Date Range, Start	July 2018
Debt Instrument, Unamortized Premium	$ 23,758
Securitized Debt Obligation Liability	8,626,823	6,937,841
Finance Receivables Transferred to Special Purpose Entities	9,549,892
Securitized Debt Obligation Liability - Gross	8,603,065
2008 Transactions [Member]
Debt Instrument, Maturity Date Range, Start	October 2014
Secured Debt	123,914
Debt Instrument, Maturity Date Range, End	April 2015
Original Note Amounts - Minimum	500,000
Original Note Amounts - Maximum	750,000
Original Weighted-Average Interest Rate - Minimum	6.00%
Original Weighted-Average Interest Rate - Maximum	10.50%
Finance Receivables Transferred to Special Purpose Entities	346,067
2009 Transactions [Member]
Debt Instrument, Maturity Date Range, Start	January 2016
Secured Debt	220,909
Debt Instrument, Maturity Date Range, End	July 2017
Original Note Amounts - Minimum	227,493
Original Note Amounts - Maximum	725,000
Original Weighted-Average Interest Rate - Minimum	2.70%
Original Weighted-Average Interest Rate - Maximum	7.50%
Finance Receivables Transferred to Special Purpose Entities	299,664
2010 Transactions [Member]
Debt Instrument, Maturity Date Range, Start	July 2017
Secured Debt	1,395,383
Debt Instrument, Maturity Date Range, End	April 2018
Original Note Amounts - Minimum	200,000
Original Note Amounts - Maximum	850,000
Original Weighted-Average Interest Rate - Minimum	2.20%
Original Weighted-Average Interest Rate - Maximum	3.80%
Finance Receivables Transferred to Special Purpose Entities	1,581,612
2011 Transactions [Member]
Secured Debt	3,104,607
Debt Instrument, Maturity Date Range, End	March 2019
Original Note Amounts - Minimum	800,000
Original Note Amounts - Maximum	1,000,000
Original Weighted-Average Interest Rate - Minimum	2.40%
Original Weighted-Average Interest Rate - Maximum	2.90%
Finance Receivables Transferred to Special Purpose Entities	3,374,366
2012 Transactions [Member]
Debt Instrument, Maturity Date Range, Start	June 2019
Secured Debt	3,758,252
Debt Instrument, Maturity Date Range, End	November 2019
Original Note Amounts - Minimum	800,000
Original Note Amounts - Maximum	1,200,000
Original Weighted-Average Interest Rate - Minimum	1.90%
Original Weighted-Average Interest Rate - Maximum	2.90%
Finance Receivables Transferred to Special Purpose Entities	$ 3,948,183

Original Note Amounts - Maximum

No definition available.

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

- Definition

Original Note Amounts - Minimum

+ References

No definition available.

+ Details

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

- Definition

Original Weighted-Average Interest Rate - Maximum

+ References

No definition available.

+ Details

Name:	acf_OriginalWeightedAverageInterestRateMaximum
Namespace Prefix:	acf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Original Weighted-Average Interest Rate - Minimum

+ References

No definition available.

+ Details

Name:	acf_OriginalWeightedAverageInterestRateMinimum
Namespace Prefix:	acf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Securitized debt issued by securitization trusts to third-party investors accounted for as secured borrowings. Such obligations are secured by restricted loans for securitization investors.

+ References

No definition available.

+ Details

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

- Definition

Securitized Debt Obligation Liability - Gross

+ References

No definition available.

+ Details

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

- Definition

Total Receivables Pledged To Securitization Trusts

+ References

No definition available.

+ Details

Name:	acf_TotalReceivablesPledgedToSecuritizationTrusts
Namespace Prefix:	acf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

When presenting a range of maturity dates, the latest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_DebtInstrumentMaturityDateRangeEnd
Namespace Prefix:	us-gaap_
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

When presenting a range of maturity dates, the earliest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years).

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDateRangeStart
Namespace Prefix:	us-gaap_
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of debt premium that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 1A

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

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

- Definition

Carrying value as of the balance sheet date , including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-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=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-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

+ Details

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