XML 74 R41.htm IDEA: XBRL DOCUMENT
v3.23.1

Investments - Maturity Table (Details) - USD ($) $ in Thousands | Mar. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 2,487,749 | $ 2,554,332
Estimated Fair Value | 2,311,062 | $ 2,342,089
2023 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 114,993 |
Estimated Fair Value | 113,061 |
2024 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 698,346 |
Estimated Fair Value | 670,601 |
2025 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 298,066 |
Estimated Fair Value | 286,613 |
2026 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 548,319 |
Estimated Fair Value | 499,306 |
2027 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 98,309 |
Estimated Fair Value | 95,902 |
2038 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 71 |
Estimated Fair Value | 73 |
2039 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 718 |
Estimated Fair Value | 719 |
2042 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 2,528 |
Estimated Fair Value | 2,227 |
2043 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 4,434 |
Estimated Fair Value | 4,055 |
2044 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 5,412 |
Estimated Fair Value | 5,057 |
2045 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 5,443 |
Estimated Fair Value | 4,940 |
2046 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 7,963 |
Estimated Fair Value | 7,165 |
2047 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 8,386 |
Estimated Fair Value | 7,586 |
2048 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 2,056 |
Estimated Fair Value | 2,001 |
2049 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 16,374 |
Estimated Fair Value | 14,836 |
2050 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 114,601 |
Estimated Fair Value | 93,786 |
2051 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 161,035 |
Estimated Fair Value | 130,855 |
2052 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 56,605 |
Estimated Fair Value | 50,153 |
2053 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 109,892 |
Estimated Fair Value | 100,141 |
2054 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 83,670 |
Estimated Fair Value | 75,428 |
2055 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 98,051 |
Estimated Fair Value | 94,030 |
2058 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 52,477 |
Estimated Fair Value | $ 52,527 |

X
- Definition Amortized cost 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://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount 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://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2026Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2038Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2039Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2042Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2043Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2044Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2045Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2046Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2047Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2048Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2049Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2050Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2051Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2052Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2053Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2054Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2055Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2058Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |