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Expected Loss to be Paid (Recovered) - Net Economic Loss Development (Benefit) (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2022 | Mar. 31, 2021
Schedule of Expected Losses to be Paid [Line Items] |  |
Net Economic Loss Development (Benefit) | $ (44) | $ 13
RMBS | UNITED STATES |  |
Schedule of Expected Losses to be Paid [Line Items] |  |
Net Economic Loss Development (Benefit) | 7 | 11
RMBS | UNITED STATES | First Lien |  |
Schedule of Expected Losses to be Paid [Line Items] |  |
Net Economic Loss Development (Benefit) | 18 | 25
RMBS | UNITED STATES | Second Lien |  |
Schedule of Expected Losses to be Paid [Line Items] |  |
Net Economic Loss Development (Benefit) | $ (11) | $ (14)

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