v3.26.1
Fair Value Measurements - Investments in Certain Other Invested Assets (Details) - USD ($)
$ in Millions
6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) $ 3,048 $ 3,456
Private Equity Funds and Hedge Funds    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) 2,891 3,264
Unfunded Commitments 1,077 1,266
Private equity funds    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) 2,757 3,090
Unfunded Commitments $ 1,077 1,266
Average original expected lives (in years) 10 years  
Private equity funds | Minimum    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Extension period (in years) 1 year  
Private equity funds | Maximum    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Extension period (in years) 2 years  
Leveraged buyout    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) $ 991 1,184
Unfunded Commitments 435 527
Real assets    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) 410 516
Unfunded Commitments 74 81
Growth equity    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) 31 172
Unfunded Commitments 13 11
Private equity secondaries    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) 303 71
Unfunded Commitments 74 98
Other    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) 1,022 1,147
Unfunded Commitments 481 549
Hedge funds    
INVESTMENTS IN CERTAIN ENTITIES CARRIED AT FAIR VALUE USING NET ASSET VALUE PER SHARE    
Fair Value Using NAV Per Share (or its equivalent) 134 174
Unfunded Commitments $ 0 $ 0