XML 203 R59.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Allowance for Loan Losses - Additional Information (Details) | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2019 | Sep. 30, 2019 | Dec. 31, 2018 | Jul. 01, 2006
Schedule Of Allowance For Credit Losses And Recorded Investment In Financing Receivables Table [Line Items] |  |  |  |
Interest rate offered to borrowers facing financial difficulty | 4.00% |  |  |
Interest rate offered to borrowers facing financial difficulty, period | 2 years |  |  |
Percentage of loans in full and interest repayment status that are subject to interest rate reductions | 7.20% |  | 6.40% |
Percentage of loans granted forbearance (as a percentage) | 50.00% |  | 57.00% |
Criteria for loans to be considered as nonperforming | 90 days |  |  |
Tier 1 of government guarantee (at least) |  |  |  | 97.00%
TDR payment default period | 60 days |  |  |
Period of loans past due that have accrued interest | 90 days |  |  |
FFELP Loans |  |  |  |
Schedule Of Allowance For Credit Losses And Recorded Investment In Financing Receivables Table [Line Items] |  |  |  |
Tier 1 of government guarantee (at least) | 97.00% |  |  |
Maximum |  |  |  |
Schedule Of Allowance For Credit Losses And Recorded Investment In Financing Receivables Table [Line Items] |  |  |  |
Interest rate offered to borrowers facing financial difficulty |  | 4.00% |  |
Minimum |  |  |  |
Schedule Of Allowance For Credit Losses And Recorded Investment In Financing Receivables Table [Line Items] |  |  |  |
Interest rate offered to borrowers facing financial difficulty |  | 2.00% |  |

X
- Definition Criteria for loans to be considered as nonperforming. + References No definition available. + Details
Name: | slm_CriteriaForLoansToBeConsideredAsNonperforming
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loans And Leases Receivable, Percentage Of Loans In Full And Interest Repayment Status That Are Subject To Interest Rate Reductions + References No definition available. + Details
Name: | slm_LoansAndLeasesReceivablePercentageOfLoansInFullAndInterestRepaymentStatusThatAreSubjectToInterestRateReductions
Namespace Prefix: | slm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loans And Leases Receivable, Period Of Interest Rate Reduction, Financial Difficulty Status + References No definition available. + Details
Name: | slm_LoansAndLeasesReceivablePeriodOfInterestRateReductionFinancialDifficultyStatus
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loans And Leases Receivable, Temporary Interest Rate Reduction, Financial Difficulty Status + References No definition available. + Details
Name: | slm_LoansAndLeasesReceivableTemporaryInterestRateReductionFinancialDifficultyStatus
Namespace Prefix: | slm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loans and Leases Receivable, Impaired, Loans Granted Forbearance Qualified as Trouble Debt Restructuring + References No definition available. + Details
Name: | slm_LoansandLeasesReceivableImpairedLoansGrantedForbearanceQualifiedasTroubleDebtRestructuring
Namespace Prefix: | slm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Payment Default Period For Troubled Debt Restructurings + References No definition available. + Details
Name: | slm_PaymentDefaultPeriodForTroubledDebtRestructurings
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of Loans Past Due That Have Accrued Interest + References No definition available. + Details
Name: | slm_PeriodofLoansPastDueThatHaveAccruedInterest
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition [Line Items] for Schedule Of Allowance For Credit Losses And Recorded Investment In Financing Receivables Table [Table] + References No definition available. + Details
Name: | slm_ScheduleOfAllowanceForCreditLossesAndRecordedInvestmentInFinancingReceivablesTableLineItems
Namespace Prefix: | slm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tier One of Government Guarantee + References No definition available. + Details
Name: | slm_TierOneofGovernmentGuarantee
Namespace Prefix: | slm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |