v3.26.1
Investments (Details) - Investment Information, Losses - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value $ 26,118 $ 5,667
Continuous unrealized loss position, less than 12 months, gross unrealized losses 396 48
Continuous unrealized loss position, 12 months or longer, fair value 31,594 37,450
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 3,131 2,801
Continuous unrealized loss position, total, fair value 57,712 43,117
Continuous unrealized loss position, total, gross unrealized losses 3,527 2,849
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 401 19
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 0 14
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 387 550
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total 790 583
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 1,166 611
Continuous unrealized loss position, less than 12 months, gross unrealized losses 16 5
Continuous unrealized loss position, 12 months or longer, fair value 1,401 1,684
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 78 76
Continuous unrealized loss position, total, fair value 2,567 2,295
Continuous unrealized loss position, total, gross unrealized losses 94 81
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 10,195 2,234
Continuous unrealized loss position, less than 12 months, gross unrealized losses 198 28
Continuous unrealized loss position, 12 months or longer, fair value 13,253 16,428
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 1,880 1,642
Continuous unrealized loss position, total, fair value 23,448 18,662
Continuous unrealized loss position, total, gross unrealized losses 2,078 1,670
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 399 18
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 0 10
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 382 550
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total 783 578
Debt securities issued by foreign governments [Member]    
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value 178 34
Continuous unrealized loss position, less than 12 months, gross unrealized losses 3 0
Continuous unrealized loss position, 12 months or longer, fair value 57 75
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 2 3
Continuous unrealized loss position, total, fair value 235 109
Continuous unrealized loss position, total, gross unrealized losses 5 3
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 2,654 437
Continuous unrealized loss position, less than 12 months, gross unrealized losses 24 2
Continuous unrealized loss position, 12 months or longer, fair value 1,319 1,835
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 132 128
Continuous unrealized loss position, total, fair value 3,973 2,272
Continuous unrealized loss position, total, gross unrealized losses 156 130
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
Corporate and all other bonds [Member]    
Investment disclosure details    
Continuous unrealized loss position, less than 12 months, fair value 11,925 2,351
Continuous unrealized loss position, less than 12 months, gross unrealized losses 155 13
Continuous unrealized loss position, 12 months or longer, fair value 15,564 17,428
Continuous unrealized loss position, 12 months or longer, gross unrealized losses 1,039 952
Continuous unrealized loss position, total, fair value 27,489 19,779
Continuous unrealized loss position, total, gross unrealized losses 1,194 965
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, 3 months or less 2 1
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 4
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, greater than 12 months 5 0
Unrealized investment losses on fixed maturity investments for which fair value is less than 80% of amortized cost, total $ 7 $ 5