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Expected Loss to be Paid (Recovered) - Net Economic Loss Development (Benefit) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
RMBS losses | $ 21 | $ 49 | $ 14 | $ 60
RMBS | United States |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
RMBS losses | (10) | (9) | (13) | (4)
RMBS | United States | First Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
RMBS losses | (2) | 0 | (3) | 0
RMBS | United States | Second Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
RMBS losses | $ (8) | $ (9) | $ (10) | $ (4)

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