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Borrowings - Securitizations (Details) - USD ($) | 1 Months Ended |  |
--- | --- | --- | ---
Aug. 31, 2020 | Feb. 29, 2020 | Mar. 31, 2021 | Dec. 31, 2020
Securities Financing Transaction [Line Items] |  |  |  |
Total Issued |  |  |  | $ 1,343,000,000
Total loan and accrued interest amount securitized at inception on-balance sheet term securitization |  |  |  | $ 1,463,230,000
2020-A |  |  |  |
Securities Financing Transaction [Line Items] |  |  |  |
Total Issued |  | $ 636,000,000 |  |
Basis spread on variable rate |  | 0.88% |  |
Weighted Average Life |  | 4 years 2 months 4 days |  |
2020-B |  |  |  |
Securities Financing Transaction [Line Items] |  |  |  |
Total Issued | $ 707,000,000 |  |  |
Basis spread on variable rate | 1.30% |  |  |
Weighted Average Life | 4 years 1 month 20 days |  |  |
Private Education Loan securitization |  |  |  |
Securities Financing Transaction [Line Items] |  |  |  |
Loans pledged as collateral |  |  | $ 1,290,000,000 |
Principal amount of collateral |  |  | 1,200,000,000 |
Capitalized interest |  |  | $ 86,000,000 |

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- 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5086-111524 + Details
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