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SECURITIES - Unrealized Loss Position (Details) $ in Thousands | Mar. 31, 2019 USD ($) security | Dec. 31, 2018 USD ($) security
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Unrealized Loss Position For: |  |
Estimated Fair Value | $ 54,652,187 | $ 65,552,879
Gross Unrealized Losses | $ (1,223,601) | $ (2,285,609)
Number of Securities (security) | security | 1,602 | 2,189
Available For Sale Securities, Continuous Unrealized Loss Positions, Less Than 12 Months |  |
Unrealized Loss Position For: |  |
Estimated Fair Value | $ 12,188,284 | $ 22,418,036
Gross Unrealized Losses | $ (197,039) | $ (432,352)
Number of Securities (security) | security | 89 | 713
Available For Sale Securities, Continuous Unrealized Loss Positions, Greater Than 12 Months |  |
Unrealized Loss Position For: |  |
Estimated Fair Value | $ 42,463,903 | $ 43,134,843
Gross Unrealized Losses | $ (1,026,562) | $ (1,853,257)
Number of Securities (security) | security | 1,513 | 1,476

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- Definition Mortgage-Backed Securities in a continuous unrealized loss position [Line Items] + References No definition available. + Details
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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
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- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
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- Definition Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
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