Additional Proceeds from Sale of Debt Securities, Available-for-sale

No definition available.

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Namespace Prefix:	slm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Vertical Risk Retention, Percentage

+ 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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27357-111563

+ Details

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

- Definition

Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26853-111562

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 11
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3151-108585

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3179-108585

+ Details

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- Details

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Borrowings - Unconsolidated VIEs Narrative (Details) - USD ($) $ in Millions						12 Months Ended
	Oct. 19, 2022	May 27, 2022	Mar. 16, 2022	May 27, 2021	Feb. 09, 2021	Dec. 31, 2022
Debt Instrument [Line Items]
Vertical risk retention interest						5.00%
2022-A
Debt Instrument [Line Items]
Vertical risk retention interest			5.00%
2022-A \| Student Loan
Debt Instrument [Line Items]
Private education loans sold			$ 973
Additional net proceeds from sales of loans held for investment, capitalized interest			95
Gain on sale			$ 10
2022-B
Debt Instrument [Line Items]
Vertical risk retention interest		5.00%
2022-B \| Student Loan
Debt Instrument [Line Items]
Private education loans sold		$ 2,000
Additional net proceeds from sales of loans held for investment, capitalized interest		107
Gain on sale		11
2022-D \| Student Loan
Debt Instrument [Line Items]
Private education loans sold		1,000
Additional net proceeds from sales of loans held for investment, capitalized interest		$ 54
Gain on sale	$ 3
2021-A
Debt Instrument [Line Items]
Vertical risk retention interest					5.00%
2021-A \| Student Loan
Debt Instrument [Line Items]
Private education loans sold					$ 2,500
Additional net proceeds from sales of loans held for investment, capitalized interest					130
Gain on sale					$ 18
2021-C
Debt Instrument [Line Items]
Vertical risk retention interest				5.00%
2021-C \| Student Loan
Debt Instrument [Line Items]
Private education loans sold				$ 505
Additional net proceeds from sales of loans held for investment, capitalized interest				27
Gain on sale				$ 4