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Expected Loss to be Paid (Recovered) - Net Economic Loss Development (Benefit) U.S. RMBS (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Schedule of Expected Losses to be Paid [Line Items] |  |  |
Net Economic Loss Development (Benefit) | $ 164 | $ (125) | $ (287)
U.S. | RMBS |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |
Net Economic Loss Development (Benefit) | (56) | (143) | (100)
First Lien | U.S. | RMBS |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |
Net Economic Loss Development (Benefit) | 7 | (36) | 0
Second Lien | U.S. | RMBS |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |
Net Economic Loss Development (Benefit) | $ (49) | $ (107) | $ (100)

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