Investments - Components of Equity Realized Gains (Losses) (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Investments, Debt and Equity Securities [Abstract] | ||
| Total net gains (losses) recognized during the period on equity securities | $ (179) | $ (185) |
| Less: Net gains (losses) recognized on equity securities sold during the period | 10 | 31 |
| Net holding period gains (losses) recognized during the period on equity securities held at period end | $ (189) | $ (216) |