v3.26.1
Fair Value Measurement - Fair Value Level 3 Rollforward Recurring Basis (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
FG VIEs’ Assets        
Fair Value Level 3 Rollforward        
Fair value at beginning of period $ 146 $ 145 $ 150 $ 147
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 3 4 3 7
Other comprehensive income (loss) 0 0 0 0
Purchases 0 0 0 0
Sales   0   0
Settlements (6) (5) (10) (10)
Consolidations   9   9
Deconsolidations 0   0  
Transfers into Level 3     0  
Fair value at end of period 143 153 143 153
Change in unrealized gains/(losses) related to financial instruments held 2 3 2 5
Assets of CIVs        
Fair Value Level 3 Rollforward        
Fair value at beginning of period   118 167 99
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss)   3 4 22
Other comprehensive income (loss)   0 0 0
Purchases   0 0 0
Sales   0   0
Settlements   0 (165) 0
Consolidations   0   0
Deconsolidations     (6)  
Transfers into Level 3     0  
Fair value at end of period 0 121 0 121
Change in unrealized gains/(losses) related to financial instruments held   3 0 22
Other        
Fair Value Level 3 Rollforward        
Fair value at beginning of period 30 6 24 5
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) (8) (1) (2) 1
Other comprehensive income (loss) 0 0 0 (1)
Purchases 0 0 0 0
Sales   0   0
Settlements 0 0 0 0
Consolidations   0   0
Deconsolidations 0   0  
Transfers into Level 3     0  
Fair value at end of period 22 5 22 5
Change in unrealized gains/(losses) related to financial instruments held (8) (1) (2) 1
Other | Location, Statement of Other Comprehensive Income, Balance [Axis]: us-gaap:OtherComprehensiveIncomeLossNetOfTax        
Total pre-tax realized and unrealized gains (losses) recorded in:        
Change in unrealized gains/(losses) related to financial instruments held 0 0 0 (1)
Financial Guaranty Variable Interest Entities        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Fair value at start of period (152) (163) (156) (164)
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) (2) (3) (1) (5)
Other comprehensive income (loss) 2 1 2 0
Settlements 5 4 8 8
Fair value at end of period (147) (161) (147) (161)
Change in unrealized gains/(losses) included in earnings related to financial instruments (1) (2) 0 (4)
Change in unrealized gains/(losses) included in OCI related to financial instruments 2 1 2 0
Obligations of state and political subdivisions | Fixed-maturity securities, available-for-sale:        
Fair Value Level 3 Rollforward        
Fair value at beginning of period 10 10 10 10
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 0 2 0 2
Other comprehensive income (loss) 0 0 0 0
Purchases 0 0 0 0
Sales   0   0
Settlements 0 (2) 0 (2)
Consolidations   0   0
Deconsolidations 0   0  
Transfers into Level 3     0  
Fair value at end of period 10 10 10 10
Obligations of state and political subdivisions | Fixed-maturity securities, available-for-sale: | Location, Statement of Other Comprehensive Income, Balance [Axis]: us-gaap:OtherComprehensiveIncomeLossNetOfTax        
Total pre-tax realized and unrealized gains (losses) recorded in:        
Change in unrealized gains/(losses) related to financial instruments held 0 0 0 0
Corporate securities | Fixed-maturity securities, available-for-sale:        
Fair Value Level 3 Rollforward        
Fair value at beginning of period 162 5 168 0
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 1 0 2 0
Other comprehensive income (loss) (3) 10 (10) 10
Purchases 0 69 0 74
Sales   0   0
Settlements 0 0 0 0
Consolidations   0   0
Deconsolidations 0   0  
Transfers into Level 3     0  
Fair value at end of period 160 84 160 84
Corporate securities | Fixed-maturity securities, available-for-sale: | Location, Statement of Other Comprehensive Income, Balance [Axis]: us-gaap:OtherComprehensiveIncomeLossNetOfTax        
Total pre-tax realized and unrealized gains (losses) recorded in:        
Change in unrealized gains/(losses) related to financial instruments held (3) 10 (10) 10
RMBS | Fixed-maturity securities, available-for-sale:        
Fair Value Level 3 Rollforward        
Fair value at beginning of period 140 144 144 145
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 2 1 4 4
Other comprehensive income (loss) 17 4 16 6
Purchases 2 0 2 0
Sales   0   0
Settlements (6) (7) (11) (13)
Consolidations   0   0
Deconsolidations 0   0  
Transfers into Level 3     0  
Fair value at end of period 155 142 155 142
RMBS | Fixed-maturity securities, available-for-sale: | Location, Statement of Other Comprehensive Income, Balance [Axis]: us-gaap:OtherComprehensiveIncomeLossNetOfTax        
Total pre-tax realized and unrealized gains (losses) recorded in:        
Change in unrealized gains/(losses) related to financial instruments held 17 4 16 6
Asset-backed securities | Fixed-maturity securities, available-for-sale:        
Fair Value Level 3 Rollforward        
Fair value at beginning of period 429 983 511 1,031
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 2 11 (2) 18
Other comprehensive income (loss) 20 10 (26) 11
Purchases 48 0 62 0
Sales   (3)   (12)
Settlements (36) (24) (82) (71)
Consolidations   0   0
Deconsolidations 0   0  
Transfers into Level 3     0  
Fair value at end of period 463 977 463 977
Asset-backed securities | Fixed-maturity securities, available-for-sale: | Location, Statement of Other Comprehensive Income, Balance [Axis]: us-gaap:OtherComprehensiveIncomeLossNetOfTax        
Total pre-tax realized and unrealized gains (losses) recorded in:        
Change in unrealized gains/(losses) related to financial instruments held 20 10 (26) 11
Fixed-Maturity Securities, Trading | Fixed-maturity securities, available-for-sale:        
Fair Value Level 3 Rollforward        
Fair value at beginning of period 8 5 4 5
Assured Life Re Acquisition     0  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 0 0 0 0
Other comprehensive income (loss) 0 0 0 0
Purchases 0 0 0 0
Sales   0   0
Settlements (4) (1) (5) (1)
Consolidations   0   0
Deconsolidations 0   0  
Transfers into Level 3     5  
Fair value at end of period 4 4 4 4
Change in unrealized gains/(losses) related to financial instruments held (1) 0 (1) 0
Funds Withheld        
Fair Value Level 3 Rollforward        
Fair value at beginning of period 296   0  
Assured Life Re Acquisition     293  
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 4   7  
Other comprehensive income (loss) 0   0  
Purchases 0   0  
Settlements (4)   (4)  
Deconsolidations 0   0  
Transfers into Level 3     0  
Fair value at end of period 296   296  
Change in unrealized gains/(losses) related to financial instruments held 4   7  
Credit Risk Contract        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Fair value at start of period (16) (30) (15) (29)
Total pre-tax realized and unrealized gains (losses) recorded in:        
Net income (loss) 2 1 3 105
Other comprehensive income (loss) 0 0 0 0
Settlements 0 0 (2) (105)
Fair value at end of period (14) (29) (14) (29)
Change in unrealized gains/(losses) included in earnings related to financial instruments $ 1 $ 1 $ 0 $ 0