XML 79 R55.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Significant Accounting Policies - Troubled Debt Restructurings and Allowance for Credit Loss Narrative (Details) - USD ($) | 9 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2022 | Dec. 31, 2023 | Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Percentage of Private Education Loans related to borrowers in school, grace or deferment |  | 25.00% | 24.00%
Period of forbearance period to be classified as TDR |  | 3 months |
Period of forbearance |  | 24 months |
Period after grace period for forbearance allowance for loans |  | 9 months |
Forbearance period after grace period for loans |  | 6 months |
Monthly payment that is smaller than the interest accrued on the loan in that month |  | $ 25 |
Financing receivable allowance for credit loss, transfer to held-to-sale | $ 2,400,000 |  |
Credit Card |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Financing receivable allowance for credit loss, transfer to held-to-sale |  | $ 2,400,000 |

X
- Definition Fixed-Pay Loan, Monthly Payment Amount, Below Monthly Accrued Interest + References No definition available. + Details
Name: | slm_FixedPayLoanMonthlyPaymentAmountBelowMonthlyAccruedInterest
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Loans and Leases Receivable, Forbearance Period after Grace Period + References No definition available. + Details
Name: | slm_LoansAndLeasesReceivableForbearancePeriodAfterGracePeriod
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loans and Leases Receivable, Period After Grace Period for Forbearance Allowance + References No definition available. + Details
Name: | slm_LoansAndLeasesReceivablePeriodAfterGracePeriodForForbearanceAllowance
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loans and Leases Receivable, Period of Forbearance + References No definition available. + Details
Name: | slm_LoansAndLeasesReceivablePeriodOfForbearance
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loans and Leases Receivable, Period of Forbearance Within Twenty-Four Month Period to be Classified as TDR + References No definition available. + Details
Name: | slm_LoansAndLeasesReceivablePeriodOfForbearanceWithinTwentyFourMonthPeriodToBeClassifiedAsTDR
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Private Education Loans Related To Borrowers In School, Grace or Deferment + References No definition available. + Details
Name: | slm_PercentageOfPrivateEducationLoansRelatedToBorrowersInSchoolGraceOrDeferment
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- 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_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of expense reversal of allowance for credit loss on financing receivable transferred to held-for-sale classification. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481990/310-10-45-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 948 -SubTopic 310 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481852/948-310-45-2 + Details
Name: | us-gaap_FinancingReceivableTransferToHeldForSaleAllowanceForCreditLossExpenseReversal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=us-gaap_CreditCardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |