Investments - Available for Sale Securities in Continuous Unrealized Loss Position (Details) $ in Millions	Dec. 31, 2025 USD ($) security	Dec. 31, 2024 USD ($) security
Fair Value
Fair Value, Less than 12 Months	$ 10,186	$ 21,662
Fair Value, 12 Months or More	12,868	18,751
Fair Value, Total	23,054	40,413
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	193	428
Gross Unrealized Losses, 12 Months or More	1,675	2,655
Gross Unrealized Losses, Total	$ 1,868	$ 3,083
Number of securities in an unrealized loss position | security	7,526	12,274
Number of individual securities in continuous unrealized loss position for longer than twelve months | security	4,065	5,984
U.S. government and government sponsored entities
Fair Value
Fair Value, Less than 12 Months	$ 167	$ 1,718
Fair Value, 12 Months or More	322	358
Fair Value, Total	489	2,076
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	8	21
Gross Unrealized Losses, 12 Months or More	78	78
Gross Unrealized Losses, Total	86	99
Obligations of states, municipalities and political subdivisions
Fair Value
Fair Value, Less than 12 Months	232	1,502
Fair Value, 12 Months or More	515	586
Fair Value, Total	747	2,088
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	8	33
Gross Unrealized Losses, 12 Months or More	45	79
Gross Unrealized Losses, Total	53	112
Non-U.S. governments
Fair Value
Fair Value, Less than 12 Months	1,524	1,964
Fair Value, 12 Months or More	1,347	3,446
Fair Value, Total	2,871	5,410
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	33	55
Gross Unrealized Losses, 12 Months or More	336	534
Gross Unrealized Losses, Total	369	589
Corporate debt
Fair Value
Fair Value, Less than 12 Months	6,031	10,347
Fair Value, 12 Months or More	8,165	10,907
Fair Value, Total	14,196	21,254
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	125	234
Gross Unrealized Losses, 12 Months or More	927	1,515
Gross Unrealized Losses, Total	1,052	1,749
RMBS
Fair Value
Fair Value, Less than 12 Months	769	3,711
Fair Value, 12 Months or More	1,764	2,147
Fair Value, Total	2,533	5,858
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	8	58
Gross Unrealized Losses, 12 Months or More	241	343
Gross Unrealized Losses, Total	249	401
CMBS
Fair Value
Fair Value, Less than 12 Months	580	1,052
Fair Value, 12 Months or More	523	992
Fair Value, Total	1,103	2,044
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	6	18
Gross Unrealized Losses, 12 Months or More	30	71
Gross Unrealized Losses, Total	36	89
CLO/ABS
Fair Value
Fair Value, Less than 12 Months	883	1,368
Fair Value, 12 Months or More	232	315
Fair Value, Total	1,115	1,683
Gross Unrealized Losses
Gross Unrealized Losses, Less than 12 Months	5	9
Gross Unrealized Losses, 12 Months or More	18	35
Gross Unrealized Losses, Total	$ 23	$ 44