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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 | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Debt and Equity Securities, FV-NI [Line Items] |  |  |  |
Derivative, Gain (Loss) on Derivative, Net | $ 5 | $ 7 | $ 19 | $ (61)
Derivative, Gain (Loss) on Derivatives, Total Net | (77) | (7) | (29) | (231)
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 | 0 |  |
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 | 4 | 7 |  |
Net gains (losses) on derivative contracts [Domain] | Futures Contracts [Member] |  |  |  |
Debt and Equity Securities, FV-NI [Line Items] |  |  |  |
Derivative, Gain (Loss) on Derivative, Net | 1 | 0 |  |
Net Change In Fair Value Of Credit Derivatives [Member] | Credit Derivatives [Member] |  |  |  |
Debt and Equity Securities, FV-NI [Line Items] |  |  |  |
Derivative, Gain (Loss) on Derivative, Net |  |  | 0 | (1)
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 | (82) | (14) | (47) | (170)
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 | (88) | (4) | (50) | (177)
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 | $ 5 | $ (10) | 3 | 7
Derivative Products [Member] | Interest Rate Swap [Member] |  |  |  |
Debt and Equity Securities, FV-NI [Line Items] |  |  |  |
Derivative, Gain (Loss) on Derivative, Net |  |  | 14 | (20)
Derivative Products [Member] | Other Contracts [Member] |  |  |  |
Debt and Equity Securities, FV-NI [Line Items] |  |  |  |
Derivative, Gain (Loss) on Derivative, Net |  |  | $ 5 | $ (41)

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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=121590274&loc=SL5618551-113959 + Details
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