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SECURITIES - Component of Agency Mortgage-Backed Securities Portfolio by Issuing Agency Concentration (Details) - Agency Mortgage-Backed Securities - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Mortgage-Backed Securities Portfolio [Line Items] |  |
Total | $ 69,150,399 | $ 66,308,788
Fannie Mae |  |
Mortgage-Backed Securities Portfolio [Line Items] |  |
Total | 64,332,620 | 60,477,303
Freddie Mac |  |
Mortgage-Backed Securities Portfolio [Line Items] |  |
Total | 4,711,281 | 5,778,809
Ginnie Mae |  |
Mortgage-Backed Securities Portfolio [Line Items] |  |
Total | $ 106,498 | $ 52,676

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- Definition The fair value as of the balance sheet date of firm holdings in mortgages, mortgage backed securities (investment instruments that represent ownership of an undivided interest in a group of mortgages, where principal and interest from the individual mortgages are used to pay investors' principal and interest on the mortgage backed security) and asset-backed securities that are primarily paid from the cash flows of a discrete pool of receivables or other financial assets (such as credit-card receivables), either fixed or revolving, that by their terms convert into cash within a finite time period. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 940 -SubTopic 320 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479035/940-320-45-2 + Details
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