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Trading Securities (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Schedule of Trading Securities [Line Items] |  |
Trading securities | $ 4,707,975 | $ 1,623,921
Trading Securities, Net Unrealized Gain (Loss) | (3,560) | 2,359
U.S. government securities [Member] |  |
Schedule of Trading Securities [Line Items] |  |
Trading securities | 9,183 | 44,264
Trading Securities, Net Unrealized Gain (Loss) | 0 | 6
Residential agency mortgage-backed securities [Member] |  |
Schedule of Trading Securities [Line Items] |  |
Trading securities | 4,669,148 | 1,504,651
Trading Securities, Net Unrealized Gain (Loss) | (3,624) | 2,293
Municipal securities [Member] |  |
Schedule of Trading Securities [Line Items] |  |
Trading securities | 19,172 | 26,196
Trading Securities, Net Unrealized Gain (Loss) | 42 | 60
Asset-backed securities [Member] |  |
Schedule of Trading Securities [Line Items] |  |
Trading securities | 0 | 14,084
Trading Securities, Net Unrealized Gain (Loss) | 0 | (21)
Other debt securities [Member] |  |
Schedule of Trading Securities [Line Items] |  |
Trading securities | 10,472 | 34,726
Trading Securities, Net Unrealized Gain (Loss) | $ 22 | $ 21

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