v3.26.1
Fair Value Measurements - Net realized and unrealized gains and losses included in income related to level 3 assets and liabilities (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets $ 22 $ 218 $ (12) $ 409
Net realized gains (losses), liabilities (2,062) (1,464) (1,632) (1,983)
Policyholder contract deposits        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities (1,809) (1,115) (1,160) (893)
Policyholder contract deposits | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Policyholder contract deposits | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Policyholder contract deposits | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Policyholder contract deposits | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities (1,809) (1,115) (1,160) (893)
Derivative liabilities, net        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 63 (98) (170) (243)
Derivative liabilities, net | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 17 17 33 32
Derivative liabilities, net | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Derivative liabilities, net | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Derivative liabilities, net | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 46 (115) (203) (275)
Fortitude Re funds withheld payable        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities (316) (251) (302) (847)
Fortitude Re funds withheld payable | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Fortitude Re funds withheld payable | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Fortitude Re funds withheld payable | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Fortitude Re funds withheld payable | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities (316) (251) (302) (847)
Market risk benefit liabilities, net        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities (164) 529 (542) (48)
Market risk benefit liabilities, net | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Market risk benefit liabilities, net | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities (165) 530 (543) (45)
Market risk benefit liabilities, net | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 0 0 0 0
Market risk benefit liabilities, net | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), liabilities 1 (1) 1 (3)
Bonds available-for-sale        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 29 204 34 372
Bonds available-for-sale | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Bonds available-for-sale | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Bonds available-for-sale | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 27 151 56 297
Bonds available-for-sale | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 2 53 (22) 75
Other bond securities        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets (12) 9 (26) 28
Other bond securities | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Other bond securities | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Other bond securities | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets (12) 9 (26) 28
Other bond securities | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Equity securities        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets (1) 0 (21) 0
Equity securities | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Equity securities | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Equity securities | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets (1) 0 (21) 0
Equity securities | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Other invested assets        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 6 5 1 9
Other invested assets | Income Statement Location [Axis]: us-gaap:InsuranceCommissionsAndFees        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Other invested assets | Income Statement Location [Axis]: us-gaap:MarketRiskBenefitChangeInFairValueGainLoss        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 0 0 0 0
Other invested assets | Income Statement Location [Axis]: us-gaap:NetInvestmentIncome        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets 5 17 (1) 21
Other invested assets | Income Statement Location [Axis]: us-gaap:RealizedInvestmentGainsLosses        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Net realized gains (losses), assets $ 1 $ (12) $ 2 $ (12)