Investments - Components of Equity Realized Gains (Losses) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Investments, Debt and Equity Securities [Abstract] | ||||
| Total net gains (losses) recognized during the period on equity securities | $ 586 | $ 358 | $ 407 | $ 173 |
| Less: Net gains (losses) recognized on equity securities sold during the period | 15 | 1 | 25 | 32 |
| Net holding period gains (losses) recognized during the period on equity securities held at period end | $ 571 | $ 357 | $ 382 | $ 141 |