v3.25.3
Investments (Details) - Investment Information, Losses - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value $ 9,177 $ 23,954
Continuous unrealized loss position, less than 12 months, gross unrealized losses 179 454
Continuous unrealized loss position, 12 months or longer, fair value 38,531 41,709
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 3,185 4,378
Continuous unrealized loss position, total, fair value 47,708 65,663
Continuous unrealized loss position, total, gross unrealized losses 3,364 4,832
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 2 437
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less 2 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less 165 43
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 642 638
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total 811 1,118
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]    
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value 192 557
Continuous unrealized loss position, less than 12 months, gross unrealized losses 0 1
Continuous unrealized loss position, 12 months or longer, fair value 2,067 2,830
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 86 168
Continuous unrealized loss position, total, fair value 2,259 3,387
Continuous unrealized loss position, total, gross unrealized losses 86 169
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total 0 0
Obligations of U.S. states, municipalities and political subdivisions [Member]    
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value 6,006 8,584
Continuous unrealized loss position, less than 12 months, gross unrealized losses 162 160
Continuous unrealized loss position, 12 months or longer, fair value 14,917 15,007
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 1,878 2,224
Continuous unrealized loss position, total, fair value 20,923 23,591
Continuous unrealized loss position, total, gross unrealized losses 2,040 2,384
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 0 366
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less 2 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less 161 43
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 641 635
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total 804 1,044
Debt securities issued by foreign governments [Member]    
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value 52 113
Continuous unrealized loss position, less than 12 months, gross unrealized losses 0 1
Continuous unrealized loss position, 12 months or longer, fair value 327 454
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 6 12
Continuous unrealized loss position, total, fair value 379 567
Continuous unrealized loss position, total, gross unrealized losses 6 13
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total 0 0
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]    
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value 1,031 7,359
Continuous unrealized loss position, less than 12 months, gross unrealized losses 7 148
Continuous unrealized loss position, 12 months or longer, fair value 1,773 1,419
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 144 188
Continuous unrealized loss position, total, fair value 2,804 8,778
Continuous unrealized loss position, total, gross unrealized losses 151 336
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 0 58
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total 0 58
Corporate and all other bonds [Member]    
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value 1,896 7,341
Continuous unrealized loss position, less than 12 months, gross unrealized losses 10 144
Continuous unrealized loss position, 12 months or longer, fair value 19,447 21,999
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 1,071 1,786
Continuous unrealized loss position, total, fair value 21,343 29,340
Continuous unrealized loss position, total, gross unrealized losses 1,081 1,930
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 2 13
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost greater than 3 months, 6 months or less 0 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less 4 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 1 3
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total $ 7 $ 16