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Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2021 | Mar. 31, 2020
Debt and Equity Securities, FV-NI [Line Items] |  |
Derivative, Gain (Loss) on Derivative, Net | $ 25 | $ (70)
Derivative, Gain (Loss) on Derivatives, Total Net | 121 | (13)
Net gains (losses) on derivative contracts [Domain] | Credit Derivatives [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Derivative, Gain (Loss) on Derivative, Net | 0 | (1)
Net gains (losses) on derivative contracts [Domain] | Interest Rate Swap [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Derivative, Gain (Loss) on Derivative, Net | 17 | (29)
Net gains (losses) on derivative contracts [Domain] | Futures Contracts [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Derivative, Gain (Loss) on Derivative, Net | 8 | (40)
Income Loss On Variable Interest Entities [Member] | Variable Interest Entity, Primary Beneficiary [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Derivative, Gain (Loss) on Derivative, Net | 96 | 57
Income Loss On Variable Interest Entities [Member] | Interest Rate Swap [Member] | Variable Interest Entity, Primary Beneficiary [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Derivative, Gain (Loss) on Derivative, Net | 97 | 47
Income Loss On Variable Interest Entities [Member] | Currency Swaps [Member] | Variable Interest Entity, Primary Beneficiary [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Derivative, Gain (Loss) on Derivative, Net | $ (2) | $ 10

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
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