Held For Investment Mortgage Finance Receivables Exited Interest Only Mortgage Loans

No definition available.

Name:	ally_HeldForInvestmentMortgageFinanceReceivablesExitedInterestOnlyMortgageLoans
Namespace Prefix:	ally_
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- Definition

Held for investment mortgage finance receivables interest only mortgage loans.

+ References

No definition available.

+ Details

Name:	ally_HeldForInvestmentMortgageFinanceReceivablesInterestOnlyMortgageLoans
Namespace Prefix:	ally_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of interest only loans which are expected to start principal amortization in current year.

+ References

No definition available.

+ Details

Name:	ally_InterestOnlyMortgagePercentageBeginningPrincipalAmortizationCurrentYear
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- Definition

Percentage of interest only loans which are expected to start amortization in the next year.

+ References

No definition available.

+ Details

Name:	ally_InterestOnlyMortgagePercentageBeginningPrincipalAmortizationNextYear
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- 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

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

+ Details

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- Details

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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_AutomobileLoanMember
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
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- Details

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- Details

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- Details

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Finance Receivables and Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 128,609	$ 129,926	$ 126,605
Unamortized premiums and discounts and deferred fees and costs	547	587
Consumer portfolio segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	90,081	87,240
Consumer portfolio segment \| Automotive loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	73,071	70,539	69,995
Consumer portfolio segment \| Real estate-backed loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	17,010	16,701	16,506
Consumer portfolio segment \| Mortgage Finance operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	15,782	15,155
Interest-only mortgage loans	$ 11	18
Interest Only Mortgage Percentage Beginning Principal Amortization Current Year	14.00%
Interest Only Mortgage Percentage Beginning Principal Amortization Next Year	44.00%
Consumer portfolio segment \| Mortgage - Legacy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 1,228	1,546
Interest-only mortgage loans	$ 234	341
Interest-only mortgage loans having exited the interest-only period	99.00%
Commercial portfolio segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 38,528	42,686	$ 40,104
Commercial portfolio segment \| Automotive loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	29,122	33,672
Commercial portfolio segment \| Real estate-backed loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	5,029	4,809
Commercial portfolio segment \| Other loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 4,377	$ 4,205