XML 70 R42.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Allowance for Loan Losses - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2015 | Dec. 31, 2014 | Jul. 01, 2006
Receivables [Abstract] |  |  |
Troubled Debt Restructuring | $ 122.1 slm_TroubledDebtRestructuring |  |
Criteria for loans to be considered as nonperforming | 90 days |  |
TDR payment default period | 60 days |  |
Tier One of Government Guarantee | 97.00%slm_TierOneofGovernmentGuarantee |  | 97.00%slm_TierOneofGovernmentGuarantee
Ffelp Loans Net | $ 741 slm_FFELPRehabilitationLoans |  |
Percentage of FFELP Rehabilitation Loans | 61.30%slm_PercentageofFFELPRehabilitationLoans | 62.10%slm_PercentageofFFELPRehabilitationLoans |
Period of loans past due that have accrued interest | 90 days |  |

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 FFELP Rehabilitation Loans + References No definition available. + Details
Name: | slm_FFELPRehabilitationLoans
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 Percentage of FFELP Rehabilitation Loans + References No definition available. + Details
Name: | slm_PercentageofFFELPRehabilitationLoans
Namespace Prefix: | slm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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 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
- Definition Troubled debt restructuring. + References No definition available. + Details
Name: | slm_TroubledDebtRestructuring
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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