XML 64 R51.htm IDEA: XBRL DOCUMENT
v3.24.1.u1

Allowance for Credit Losses - Loan Portfolio Stratified by Key Credit Quality Indicators (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2024 | Mar. 31, 2023 | Dec. 31, 2023
% of Balance |  |  |
Current period gross charge-offs, total | $ 93,997 | $ 96,082 |
Current period recoveries, total | 11,314 | 11,997 |
Current period net charge-offs, total | 82,683 | $ 84,085 |
Consumer Portfolio Segment | Student Loan |  |  |
% of Balance |  |  |
Current period gross charge-offs, Year 1 | (7) |  | $ (1,812)
Current period gross charge-offs, Year 2 | (2,683) |  | (31,032)
Current period gross charge-offs, Year 3 | (13,167) |  | (70,331)
Current period gross charge-offs, Year 4 | (14,125) |  | (49,624)
Current period gross charge-offs, Year 5 | (9,561) |  | (50,585)
Current period gross charge-offs, After Year 5 | (54,331) |  | (216,711)
Current period gross charge-offs, total | 93,874 |  | 420,095
Current period recoveries, Year 1 | 0 |  | 172
Current period recoveries, Year 2 | 212 |  | 2,342
Current period recoveries, Year 3 | 1,397 |  | 6,496
Current period recoveries, Year 4 | 1,518 |  | 4,923
Current period recoveries, Year 5 | 1,033 |  | 5,260
Current period recoveries, After Year 5 | 7,154 |  | 27,175
Current period recoveries, total | 11,314 |  | 46,368
Current period net charge-offs, Year 1 | (7) |  | (1,640)
Current period net charge-offs, Year 2 | (2,471) |  | (28,690)
Current period recoveries, Year 3 | (11,770) |  | (63,835)
Current period recoveries, Year 4 | (12,607) |  | (44,701)
Current period recoveries, Year 5 | (8,528) |  | (45,325)
Current period recoveries, After Year 5 | (47,177) |  | (189,536)
Current period net charge-offs, total | 82,560 |  | 373,727
Total accrued interest by origination vintage, Year 1 | 15,497 |  | 177,959
Total accrued interest by origination vintage, Year 2 | 281,098 |  | 408,800
Total accrued interest by origination vintage, Year 3 | 365,340 |  | 269,978
Total accrued interest by origination vintage, Year 4 | 240,093 |  | 152,094
Total accrued interest by origination vintage, Year 5 | 138,852 |  | 116,618
Total accrued interest by origination vintage, After Year 5 | 317,107 |  | 229,116
Total accrued interest by origination vintage | 1,357,987 |  | 1,354,565
Consumer Portfolio Segment | Student Loan | With and without cosigners |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | 926,224 |  | 4,490,119
Year 2 | 5,803,342 |  | 5,088,739
Year 3 | 3,994,361 |  | 2,937,422
Year 4 | 2,454,339 |  | 1,819,089
Year 5 | 1,606,219 |  | 1,632,300
After Year 5 | 6,167,861 |  | 5,058,175
Loan type | $ 20,952,346 |  | $ 21,025,844
% of Balance |  |  |
Total in percent | 100.00% |  | 100.00%
Consumer Portfolio Segment | Student Loan | With cosigner |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 814,592 |  | $ 3,903,676
Year 2 | 5,130,203 |  | 4,428,163
Year 3 | 3,451,511 |  | 2,516,380
Year 4 | 2,089,098 |  | 1,535,308
Year 5 | 1,347,339 |  | 1,378,699
After Year 5 | 5,440,233 |  | 4,529,768
Loan type | $ 18,272,976 |  | $ 18,291,994
% of Balance |  |  |
Private education loans | 87.00% |  | 87.00%
Consumer Portfolio Segment | Student Loan | Without cosigner |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 111,632 |  | $ 586,443
Year 2 | 673,139 |  | 660,576
Year 3 | 542,850 |  | 421,042
Year 4 | 365,241 |  | 283,781
Year 5 | 258,880 |  | 253,601
After Year 5 | 727,628 |  | 528,407
Loan type | $ 2,679,370 |  | $ 2,733,850
% of Balance |  |  |
Private education loans | 13.00% |  | 13.00%
Consumer Portfolio Segment | Student Loan | FICO at Origination |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 926,224 |  | $ 4,490,119
Year 2 | 5,803,342 |  | 5,088,739
Year 3 | 3,994,361 |  | 2,937,422
Year 4 | 2,454,339 |  | 1,819,089
Year 5 | 1,606,219 |  | 1,632,300
After Year 5 | 6,167,861 |  | 5,058,175
Loan type | $ 20,952,346 |  | $ 21,025,844
% of Balance |  |  |
Total in percent | 100.00% |  | 100.00%
Consumer Portfolio Segment | Student Loan | FICO at Origination | Less than 670 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 61,789 |  | $ 328,199
Year 2 | 424,857 |  | 395,526
Year 3 | 316,552 |  | 208,696
Year 4 | 176,921 |  | 118,935
Year 5 | 105,953 |  | 137,494
After Year 5 | 546,958 |  | 451,613
Loan type | $ 1,633,030 |  | $ 1,640,463
% of Balance |  |  |
Private education loans at origination | 8.00% |  | 8.00%
Consumer Portfolio Segment | Student Loan | FICO at Origination | 670-699 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 129,467 |  | $ 635,642
Year 2 | 816,049 |  | 704,642
Year 3 | 553,845 |  | 400,744
Year 4 | 332,430 |  | 254,762
Year 5 | 226,123 |  | 257,840
After Year 5 | 1,041,796 |  | 868,777
Loan type | $ 3,099,710 |  | $ 3,122,407
% of Balance |  |  |
Private education loans at origination | 15.00% |  | 15.00%
Consumer Portfolio Segment | Student Loan | FICO at Origination | 700-749 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 288,936 |  | $ 1,383,779
Year 2 | 1,783,230 |  | 1,586,783
Year 3 | 1,243,850 |  | 934,033
Year 4 | 779,798 |  | 590,401
Year 5 | 522,793 |  | 545,333
After Year 5 | 2,082,333 |  | 1,709,299
Loan type | $ 6,700,940 |  | $ 6,749,628
% of Balance |  |  |
Private education loans at origination | 32.00% |  | 32.00%
Consumer Portfolio Segment | Student Loan | FICO at Origination | Greater than or equal to 750 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 446,032 |  | $ 2,142,499
Year 2 | 2,779,206 |  | 2,401,788
Year 3 | 1,880,114 |  | 1,393,949
Year 4 | 1,165,190 |  | 854,991
Year 5 | 751,350 |  | 691,633
After Year 5 | 2,496,774 |  | 2,028,486
Loan type | $ 9,518,666 |  | $ 9,513,346
% of Balance |  |  |
Private education loans at origination | 45.00% |  | 45.00%
Consumer Portfolio Segment | Student Loan | FICO Refreshed |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 926,224 |  | $ 4,490,119
Year 2 | 5,803,342 |  | 5,088,739
Year 3 | 3,994,361 |  | 2,937,422
Year 4 | 2,454,339 |  | 1,819,089
Year 5 | 1,606,219 |  | 1,632,300
After Year 5 | 6,167,861 |  | 5,058,175
Loan type | $ 20,952,346 |  | $ 21,025,844
% of Balance |  |  |
Total in percent | 100.00% |  | 100.00%
Consumer Portfolio Segment | Student Loan | FICO Refreshed | Less than 670 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 84,355 |  | $ 495,451
Year 2 | 669,427 |  | 638,381
Year 3 | 541,494 |  | 379,738
Year 4 | 335,868 |  | 217,956
Year 5 | 205,407 |  | 214,665
After Year 5 | 951,407 |  | 791,875
Loan type | $ 2,787,958 |  | $ 2,738,066
% of Balance |  |  |
Private education loans at origination | 13.00% |  | 13.00%
Consumer Portfolio Segment | Student Loan | FICO Refreshed | 670-699 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 129,421 |  | $ 616,684
Year 2 | 789,950 |  | 672,777
Year 3 | 514,154 |  | 365,674
Year 4 | 299,737 |  | 193,462
Year 5 | 167,203 |  | 176,963
After Year 5 | 671,160 |  | 564,245
Loan type | $ 2,571,625 |  | $ 2,589,805
% of Balance |  |  |
Private education loans at origination | 12.00% |  | 12.00%
Consumer Portfolio Segment | Student Loan | FICO Refreshed | 700-749 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 286,786 |  | $ 1,347,094
Year 2 | 1,700,049 |  | 1,477,310
Year 3 | 1,127,465 |  | 836,747
Year 4 | 678,404 |  | 498,414
Year 5 | 430,414 |  | 445,244
After Year 5 | 1,643,152 |  | 1,361,073
Loan type | $ 5,866,270 |  | $ 5,965,882
% of Balance |  |  |
Private education loans at origination | 28.00% |  | 28.00%
Consumer Portfolio Segment | Student Loan | FICO Refreshed | Greater than or equal to 750 |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 425,662 |  | $ 2,030,890
Year 2 | 2,643,916 |  | 2,300,271
Year 3 | 1,811,248 |  | 1,355,263
Year 4 | 1,140,330 |  | 909,257
Year 5 | 803,195 |  | 795,428
After Year 5 | 2,902,142 |  | 2,340,982
Loan type | $ 9,726,493 |  | $ 9,732,091
% of Balance |  |  |
Private education loans at origination | 47.00% |  | 47.00%
Consumer Portfolio Segment | Student Loan | Seasoning |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 926,224 |  | $ 4,490,119
Year 2 | 5,803,342 |  | 5,088,739
Year 3 | 3,994,361 |  | 2,937,422
Year 4 | 2,454,339 |  | 1,819,089
Year 5 | 1,606,219 |  | 1,632,300
After Year 5 | 6,167,861 |  | 5,058,175
Loan type | $ 20,952,346 |  | $ 21,025,844
% of Balance |  |  |
Total in percent | 100.00% |  | 100.00%
Consumer Portfolio Segment | Student Loan | Seasoning | 1-12 payments |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 484,203 |  | $ 2,514,079
Year 2 | 3,024,087 |  | 740,450
Year 3 | 508,182 |  | 440,293
Year 4 | 323,857 |  | 245,631
Year 5 | 191,566 |  | 208,941
After Year 5 | 433,762 |  | 332,608
Loan type | $ 4,965,657 |  | $ 4,482,002
% of Balance |  |  |
Seasoning based on monthly scheduled payments due from 1-12 payments | 24.00% |  | 21.00%
Consumer Portfolio Segment | Student Loan | Seasoning | 13-24 payments |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 0 |  | $ 0
Year 2 | 277,441 |  | 2,675,956
Year 3 | 2,095,039 |  | 303,045
Year 4 | 206,882 |  | 167,532
Year 5 | 147,749 |  | 165,577
After Year 5 | 467,866 |  | 384,760
Loan type | $ 3,194,977 |  | $ 3,696,870
% of Balance |  |  |
Seasoning based on monthly scheduled payments due from 13 - 24 payments | 15.00% |  | 18.00%
Consumer Portfolio Segment | Student Loan | Seasoning | 25-36 payments |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 0 |  | $ 0
Year 2 | 0 |  | 0
Year 3 | 156,087 |  | 1,524,834
Year 4 | 1,301,243 |  | 195,091
Year 5 | 128,581 |  | 129,571
After Year 5 | 559,089 |  | 456,448
Loan type | $ 2,145,000 |  | $ 2,305,944
% of Balance |  |  |
Seasoning based on monthly scheduled payments due from 25 - 36 payments | 10.00% |  | 11.00%
Consumer Portfolio Segment | Student Loan | Seasoning | 37-48 payments |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 0 |  | $ 0
Year 2 | 0 |  | 0
Year 3 | 0 |  | 0
Year 4 | 80,631 |  | 902,938
Year 5 | 798,248 |  | 208,521
After Year 5 | 529,743 |  | 446,350
Loan type | $ 1,408,622 |  | $ 1,557,809
% of Balance |  |  |
Seasoning based on monthly scheduled payments due from 37 - 48 payments | 7.00% |  | 7.00%
Consumer Portfolio Segment | Student Loan | Seasoning | More than 48 payments |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 0 |  | $ 0
Year 2 | 0 |  | 0
Year 3 | 0 |  | 0
Year 4 | 0 |  | 116
Year 5 | 71,116 |  | 706,097
After Year 5 | 3,564,277 |  | 2,985,015
Loan type | $ 3,635,393 |  | $ 3,691,228
% of Balance |  |  |
Seasoning based on monthly scheduled payments due from more than 48 payments | 17.00% |  | 18.00%
Consumer Portfolio Segment | Student Loan | Seasoning | Not yet in repayment |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Year 1 | $ 442,021 |  | $ 1,976,040
Year 2 | 2,501,814 |  | 1,672,333
Year 3 | 1,235,053 |  | 669,250
Year 4 | 541,726 |  | 307,781
Year 5 | 268,959 |  | 213,593
After Year 5 | 613,124 |  | 452,994
Loan type | $ 5,602,697 |  | $ 5,291,991
% of Balance |  |  |
Seasoning based on monthly scheduled payments due from not yet in repayment | 27.00% |  | 25.00%

X
- Definition Financing Receivable, Accrued Interest, Origination Interest, Originated Five or More Years before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAccruedInterestOriginationInterestOriginatedFiveOrMoreYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Accrued Interest, Origination Vintage, before Allowance for Credit Loss + References No definition available. + Details
Name: | slm_FinancingReceivableAccruedInterestOriginationVintageBeforeAllowanceForCreditLoss
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Accrued interest, Origination Vintage, Originated Four Years before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAccruedInterestOriginationVintageOriginatedFourYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Accrued Interest, Origination Vintage, Originated in Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAccruedInterestOriginationVintageOriginatedInCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Accrued Interest, Origination Vintage, Originated in Fiscal Year before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAccruedInterestOriginationVintageOriginatedInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Accrued interest, Origination Vintage, Originated Three Years before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAccruedInterestOriginationVintageOriginatedThreeYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Accrued interest, Origination Vintage, Originated Two Years before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAccruedInterestOriginationVintageOriginatedTwoYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Writeoff, Originated Five Or More Years Before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestWriteoffOriginatedFiveOrMoreYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Writeoff, Originated Four Years Before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestWriteoffOriginatedFourYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Writeoff, Originated In Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestWriteoffOriginatedInCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Writeoff, Originated In Fiscal Year Before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestWriteoffOriginatedInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Writeoff, Originated Three Years Before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestWriteoffOriginatedThreeYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Writeoff, Originated Two Years Before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterestWriteoffOriginatedTwoYearsBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Recovery, Originated Five Or More Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFiveOrMoreYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Recovery, Originated Four Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFourYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Recovery, Originated In Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedInCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Recovery, Originated In Fiscal Year Before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Recovery, Originated Three Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedThreeYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Recovery, Originated Two Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedTwoYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Originated Five Or More Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedFiveOrMoreYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Originated Four Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedFourYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Originated In Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedInCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Originated In Fiscal Year Before Latest Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Originated Three Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedThreeYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery, Originated Two Years Before Current Fiscal Year + References No definition available. + Details
Name: | slm_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedTwoYearsBeforeCurrentFiscalYear
Namespace Prefix: | slm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percent Of Balance + References No definition available. + Details
Name: | slm_PercentOfBalanceAbstract
Namespace Prefix: | slm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percent of private loans + References No definition available. + Details
Name: | slm_PercentOfPrivateLoans
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Private Education Loans At Origination + References No definition available. + Details
Name: | slm_PrivateEducationLoansAtOrigination
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Private education loans gross in percent. + References No definition available. + Details
Name: | slm_PrivateEducationLoansGrossPercentage
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Seasoning based on monthly scheduled payments due from more than forty eight payments in percent + References No definition available. + Details
Name: | slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromMoreThanFortyEightPaymentsInPercent
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Seasoning based on monthly scheduled payments due from not yet in repayment in percent + References No definition available. + Details
Name: | slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromNotYetInRepaymentInPercent
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Seasoning based on monthly scheduled payments due from one to twelve payments in percent. + References No definition available. + Details
Name: | slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromOneToTwelvePaymentsInPercent
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Seasoning based on monthly scheduled payments due from thirteen to twenty four payments in percent. + References No definition available. + Details
Name: | slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromThirteenToTwentyFourPaymentsInPercent
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Seasoning based on monthly scheduled payments due from thirty seven to forty eight payments in percent. + References No definition available. + Details
Name: | slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromThirtySevenToFortyEightPaymentsInPercent
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Seasoning based on monthly scheduled payments due from thirteen to twenty four payments in percent + References No definition available. + Details
Name: | slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromTwentyFiveToThirtySixPaymentsInPercent
Namespace Prefix: | slm_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
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_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of decrease (increase) in allowance for credit loss on financing receivable from writeoff (recovery). Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated in current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_StudentLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | slm_CreditQualityIndicatorsAxis=slm_CosignerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | slm_CreditQualityIndicatorsAxis=slm_WithCosignerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | slm_CreditQualityIndicatorsAxis=slm_WithoutCosignerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | slm_CreditQualityIndicatorsAxis=slm_SchoolFicoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditScoreFicoAxis=slm_FICOscorelessthan670Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditScoreFicoAxis=slm_FICOscore670699Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditScoreFicoAxis=slm_FICOscore700749Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditScoreFicoAxis=slm_FICOscoregreaterthan750Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | slm_CreditQualityIndicatorsAxis=slm_SchoolFICORefreshedAmountsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | slm_CreditQualityIndicatorsAxis=slm_RepaymentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromOneToTwelvePaymentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromThirteenToTwentyFourPaymentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromTwentyFiveToThirtySixPaymentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromThirtySevenToFortyEightPaymentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromMoreThanFortyEightPaymentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=slm_SeasoningBasedOnMonthlyScheduledPaymentsDueFromNotYetInRepaymentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |