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SECURITIES - Additional Information (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract] |  |
Residential Investment securities sold, carrying value | $ 10,500.0 | $ 463.4
Residential Investment securities sold, net realized gain (loss) | $ (92.5) | $ 13.0

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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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(h)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
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- References No definition available. + Details
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