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Expected Loss to be Paid (Recovered) - Net Expected Loss to be Paid (Recovered) Roll Forward (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Net expected loss to be paid (recovered), beginning of period | $ 505 | $ 522 | $ 411
Accretion of discount | 16 | 20 | 16
Changes in discount rates | 4 | 3 | (115)
Changes in timing and assumptions | (23) | 141 | (26)
Total economic loss development (benefit) | (3) | 164 | (125)
Net (paid) recovered losses | (396) | (181) | 236
Net expected loss to be paid (recovered), end of period | $ 106 | $ 505 | 522
Weighted average risk free discount rate | 4.38% | 4.09% |
Period after the end of the reporting period within which the ceded paid losses are typically settled (in days) | 45 days |  |
Public finance |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Net expected loss to be paid (recovered), beginning of period | $ 418 | $ 412 | 209
Total economic loss development (benefit) | 72 | 212 | 17
Net (paid) recovered losses | (374) | (206) | 186
Net expected loss to be paid (recovered), end of period | 116 | 418 | 412
Other structured finance |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Net expected loss to be paid (recovered), beginning of period | 44 | 44 | 52
Total economic loss development (benefit) | 0 | 8 | 1
Net (paid) recovered losses | (11) | (8) | (9)
Net expected loss to be paid (recovered), end of period | 33 | 44 | 44
Structured finance |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Net expected loss to be paid (recovered), beginning of period | 87 | 110 | 202
Total economic loss development (benefit) | (75) | (48) | (142)
Net (paid) recovered losses | (22) | 25 | 50
Net expected loss to be paid (recovered), end of period | (10) | 87 | 110
U.S. | Public finance |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Net expected loss to be paid (recovered), beginning of period | 398 | 403 | 197
Total economic loss development (benefit) | (9) | 201 | 19
Net (paid) recovered losses | (371) | (206) | 187
Net expected loss to be paid (recovered), end of period | 18 | 398 | 403
U.S. | RMBS |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Net expected loss to be paid (recovered), beginning of period | 43 | 66 | 150
Total economic loss development (benefit) | (75) | (56) | (143)
Net (paid) recovered losses | (11) | 33 | 59
Net expected loss to be paid (recovered), end of period | (43) | 43 | 66
Non U.S. | Public finance |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Net expected loss to be paid (recovered), beginning of period | 20 | 9 | 12
Total economic loss development (benefit) | 81 | 11 | (2)
Net (paid) recovered losses | (3) | 0 | (1)
Net expected loss to be paid (recovered), end of period | $ 98 | $ 20 | $ 9
Minimum |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Risk free discount rate | 1.98% | 1.90% |
Maximum |  |  |
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward] |  |  |
Risk free discount rate | 5.22% | 5.40% |

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