Investments - Gross Realized Gains and Gross Realized Losses from Sales or Maturities of Available for Sale Securities (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Investments, Debt and Equity Securities [Abstract] | |||
| Gross Realized Gains | $ 72 | $ 81 | $ 130 |
| Gross Realized Losses | 665 | 700 | 865 |
| Aggregate fair value of available for sale securities sold | 12,400 | 13,700 | 15,700 |
| Net Investment Income [Line Items] | |||
| Net realized gains (losses) | (593) | (619) | (735) |
| Fortitude RE Funds Withheld Assets | |||
| Net Investment Income [Line Items] | |||
| Net realized gains (losses) | $ (70) | $ (36) | $ (67) |