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Expected Loss to be Paid (Recovered) - Net Economic Loss Development (Benefit) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2026 | Mar. 31, 2025 | Dec. 31, 2025 | Dec. 31, 2024
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | $ 141 | $ 150 | $ 101 | $ 106
RMBS losses | 44 | (15) |  |
Changes in discount rates | (4) | 5 |  |
RMBS | United States |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | (48) | (37) | $ (54) | $ (43)
RMBS losses | (2) | (3) |  |
Changes in discount rates | $ 0 | 1 |  |
Weighted average discount rate | 4.00% |  | 3.84% |
RMBS | United States | Minimum |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Range of discount rates | 3.63% |  | 3.45% |
RMBS | United States | Maximum |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Range of discount rates | 5.06% |  | 4.97% |
RMBS | United States | First Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | $ 92 |  | $ 90 |
RMBS losses | $ 0 | 2 |  |
RMBS | United States | First Lien | Weighted Average | Base Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Percent of deferred loan balances to be recovered | 50.00% |  | 50.00% |
RMBS | United States | Second Lien |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | $ (140) |  | $ (144) |
RMBS losses | $ (2) | $ (5) |  |
Percent of deferred loan balances to be recovered | 2.00% |  |  |
RMBS | United States | Second Lien | Weighted Average | Base Scenario |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Percent of deferred loan balances to be recovered | 60.00% |  | 60.00% |

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