v3.25.2
Expected Loss to be Paid (Recovered) - Net Expected Loss to be Paid After Net Expected Recoveries for Breaches of R&W Rollforward (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
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 $ 150 $ 433 $ 106 $ 505 $ 505
Accretion of discount 2 4 3 9  
Changes in discount rates 1 1 6 (2)  
Changes in timing and assumptions 33 16 12 7  
Total economic loss development (benefit) 36 21 21 14  
Net (paid) recovered losses 0 (7) 59 (72)  
Net expected loss to be paid (recovered), end of period 186 447 186 $ 447 106
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 157 398 116 $ 418 418
Total economic loss development (benefit) 42 29 95 26  
Net (paid) recovered losses (7) (16) (19) (33)  
Net expected loss to be paid (recovered), end of period 192 411 192 411 116
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 30 37 33 44 44
Total economic loss development (benefit) 0 2 (65) 1  
Net (paid) recovered losses (1) (3) 61 (9)  
Net expected loss to be paid (recovered), end of period 29 36 29 36 33
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 (7) 35 (10) 87 87
Total economic loss development (benefit) (6) (8) (74) (12)  
Net (paid) recovered losses 7 9 78 (39)  
Net expected loss to be paid (recovered), end of period (6) 36 $ (6) 36 $ (10)
Minimum          
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward]          
Risk free discount rate     1.84%   1.98%
Maximum          
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward]          
Risk free discount rate     5.48%   5.22%
Weighted Average          
Present Value of Net Expected Loss and Loss Adjustment Expenses to be Paid [Roll Forward]          
Risk free discount rate     4.15%   4.38%
United States | 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 35 378 $ 18 398 $ 398
Total economic loss development (benefit) 24 12 53 9  
Net (paid) recovered losses (6) (16) (18) (33)  
Net expected loss to be paid (recovered), end of period 53 374 53 374 18
United States | 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 (37) (2) (43) 43 43
Total economic loss development (benefit) (6) (10) (9) (13)  
Net (paid) recovered losses 8 12 17 (30)  
Net expected loss to be paid (recovered), end of period (35) 0 (35) 0 (43)
Non-U.S. public finance | 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 122 20 98 20 20
Total economic loss development (benefit) 18 17 42 17  
Net (paid) recovered losses (1) 0 (1) 0  
Net expected loss to be paid (recovered), end of period $ 139 $ 37 $ 139 $ 37 $ 98