Fair Value Measurements - Gains or losses recorded related to fair value option (Details) - Fair Value Option - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
|
| Fair Value, Option, Quantitative Disclosures | |||
| Fair value option gain (loss) | $ 719 | $ (373) | $ 1,704 |
| Other bond securities | |||
| Fair Value, Option, Quantitative Disclosures | |||
| Fair value option gain (loss) | 382 | (822) | (12) |
| Alternative investments | |||
| Fair Value, Option, Quantitative Disclosures | |||
| Fair value option gain (loss) | 334 | 224 | 1,650 |
| Long-term debt | |||
| Fair Value, Option, Quantitative Disclosures | |||
| Fair value option gain (loss) | $ 3 | $ 225 | $ 66 |