| **Fair Value (Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets) (Details) $ in Millions** | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------|-----------------------|
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Estimated fair value                                                                                                                                    | $ 43,116              | $ 39,980              |
| Fixed maturity securities | Discounted cash flow                                                                                                        |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Estimated fair value                                                                                                                                    | $ 1,495               | $ 1,177               |
| Credit spread | Discounted cash flow | Minimum                                                                                                          |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Debt securities, available-for-sale, measurement Input                                                                                                  | 0.01                  | 0.01                  |
| Credit spread | Discounted cash flow | Maximum                                                                                                          |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Debt securities, available-for-sale, measurement Input                                                                                                  | 0.07                  | 0.08                  |
| Credit spread | Discounted cash flow | Weighted Average                                                                                                 |                  |                  |
| **Fair Value Inputs, Assets, Quantitative Information [Line Items]**                                                                                    |                  |                  |
| Debt securities, available-for-sale, measurement Input                                                                                                  | 0.02                  | 0.02                  |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
+ References
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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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