XML 80 R68.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Commitments, Contingencies and Guarantees - Additional Information (Detail) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2016 USD ($) attorney_general | May 13, 2014 USD ($)
Loss Contingencies [Line Items] |  |
Contractual obligation | $ 1,800,000,000 |
Other liabilities reserve | $ 1,600,000 |
Loss contingency, loss emergence period | 1 year |
FDIC civil monetary penalties |  | $ 3,300,000
Number of Attorney Generals | attorney_general | 2 |
Maximum |  |
Loss Contingencies [Line Items] |  |
Contingency refund (up to) |  | $ 30,000,000

X
- Definition Contingency refund + References No definition available. + Details
Name: | slm_Contingencyrefund
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition FDIC civil monetary penalties + References No definition available. + Details
Name: | slm_FDICcivilmonetarypenalties
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Loss Contingency, Loss Emergence Period + References No definition available. + Details
Name: | slm_LossContingencyLossEmergencePeriod
Namespace Prefix: | slm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Attorney Generals + References No definition available. + Details
Name: | slm_NumberofAttorneyGenerals
Namespace Prefix: | slm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Other Liabilities Reserve + References No definition available. + Details
Name: | slm_OtherLiabilitiesReserve
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments. + References No definition available. + Details
Name: | us-gaap_ContractualObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |