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SECURITIES - Additional Information (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
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Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract] |  |  |  |
Residential Investment securities sold, carrying value | $ 11,100.0 | $ 9,100.0 | $ 30,700.0 | $ 14,500.0
Residential Investment securities sold, net realized gains (losses) | $ 76.3 | $ (322.4) | $ (50.6) | $ (372.5)

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- Definition Carrying value of mortgage backed securities sold during period. + References No definition available. + Details
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- Definition Net gain (loss) resulting from the sales of securitized, pay-through debt securities collateralized by real estate mortgage loans (mortgages). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(h)) -URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260 + Details
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- References No definition available. + Details
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