Contractual Maturity

No definition available.

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- Definition

Debt Instrument, Contractual Maturity, Term, Amortization Period

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Contractual Maturity, Term, Revolving Period

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Unused Borrowing Capacity Fee, Percentage

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Estimated weighted average life of student loans.

+ References

No definition available.

+ Details

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- Definition

Lendable value of collateral

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Percent Outstanding of Borrowing Capacity

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Line of Credit, Required Ownership Interest

+ References

No definition available.

+ Details

Name:	slm_LineofCreditRequiredOwnershipInterest
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loans Securitized or Asset-backed Financing Arrangement, Ownership Interest, Amount

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loans Securitized or Asset-backed Financing Arrangement, Ownership Interest, Percentage

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Uncommitted Federal Funds

+ References

No definition available.

+ Details

Name:	slm_UncommittedFederalFunds
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=51814546&loc=d3e107314-111719

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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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

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5086-111524

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

This is the principal amount outstanding for loans which are in the process of being securitized as of the date of the statement of financial position (across all types of loans).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51814546&loc=d3e107314-111719

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

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Balance Type:	credit
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- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.(a),16(a)(1))
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-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 13
-Subparagraph 2, 3
-Article 9

+ Details

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Balance Type:	credit
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- Details

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- Details

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Borrowings - Additional (Details) - USD ($)		12 Months Ended
Borrowings - Additional (Details) - USD ($)	Jul. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Oct. 27, 2015	Apr. 23, 2015	Dec. 19, 2014
Debt Instrument [Line Items]
Secured borrowings			$ 0
Amount drawn and outstanding under ABCP facility		$ 500,175,000
Discretionary uncommitted federal funds line of credit		100,000,000
Lendable value of collateral		$ 1,700,000,000	$ 1,400,000,000
Estimated weighted average life of student loans		6 years 2 months 6 days	6 years 2 months 12 days
Private Education Loans
Debt Instrument [Line Items]
Private education loan term accounted for as a secured financing	$ 714,000,000
Loans sold to third parties	630,800,000			$ 701,000,000	$ 738,000,000
Gross profit raised from loans sold to third parties	$ 623,000,000
Loans pledged as collateral		$ 687,300,000
Class A and B Notes
Debt Instrument [Line Items]
Ownership interest percentage on asset-backed financing	5.00%
Ownership interest amount of securitized or asset backed loan	$ 33,000,000
Estimated weighted average life of student loans	4 years 9 months 18 days
Class C Notes
Debt Instrument [Line Items]
Ownership interest percentage on asset-backed financing	100.00%
Ownership interest amount of securitized or asset backed loan	$ 50,000,000
Residual Certificates
Debt Instrument [Line Items]
Ownership interest percentage on asset-backed financing	100.00%
ABCP borrowings
Debt Instrument [Line Items]
Contractual maturity related to ABCP facility		2 years
Revolving period of contractual maturity		1 year
Amortization period of contractual maturity		1 year
Amount drawn and outstanding under ABCP facility		$ 500,175,000
Loans pledged as collateral		$ 923,700,000
London Interbank Offered Rate (LIBOR) \| Class A and B Notes
Debt Instrument [Line Items]
Basis spread on variable rate	1.53%
Commercial Paper \| ABCP borrowings
Debt Instrument [Line Items]
Private education loan funding						$ 750,000,000
Ownership interest retained in ABCP facility (as a percent)		5.00%				5.00%
Line of Credit, Required Ownership Interest						$ 37,500,000
Funds available to draw						$ 712,500,000
Unused borrowing capacity fee (as a percent)		0.40%
Commercial Paper \| London Interbank Offered Rate (LIBOR) \| ABCP borrowings
Debt Instrument [Line Items]
Basis spread on variable rate		0.80%