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Arrangements with Navient Corporation (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2018 | Dec. 31, 2020 | Mar. 31, 2020 | Apr. 30, 2014
Related Party Transaction [Line Items] |  |  |  |
Remaining balance of indemnification receivable in connection with the spin-off |  | $ 7 |  | $ 27
Minimum days past due for spin off loan purchase |  | 90 days |  |
Period of hardship forbearance |  | 6 months |  |
Discontinued Operations, Disposed of by Sale |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Split Loans portfolio sales price | $ 43 |  | $ 43 |
Gains on sales of loans, net | $ 2 |  |  |

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- Definition Deferred Tax Assets, Remaining Balance of Indemnification Receivable In Connection with The Spin-Off + References No definition available. + Details
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- Definition Reflects the net positive or negative amount derived from subtracting from net proceeds of sale and the carrying amounts, net of allocated reserves, of financial assets transferred to third parties in transactions that qualify for sales treatment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121570589&loc=d3e107425-111719 + Details
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