| **Revenue and Interest Recognized in Income (Details) - Life Policy Reserves - USD ($) $ in Millions** | 12 Months Ended |
|--------------------------------------------------------------------------------------------------------|-----------------|
||
| **Liability for Future Policy Benefit, Activity**                                                      |            |   |   |
| Gross premiums                                                                                         | $ 341           | $ 327 | $ 317 |
| Interest accretion                                                                                     | 71              | 68 | 68 |
| Term Life Insurance                                                                                    |            |   |   |
| **Liability for Future Policy Benefit, Activity**                                                      |            |   |   |
| Gross premiums                                                                                         | 289             | 280 | 270 |
| Interest accretion                                                                                     | 49              | 47 | 47 |
| Whole Life Insurance                                                                                   |            |   |   |
| **Liability for Future Policy Benefit, Activity**                                                      |            |   |   |
| Gross premiums                                                                                         | 52              | 47 | 47 |
| Interest accretion                                                                                     | $ 22            | $ 21 | $ 21 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of gross premium income recognized for liability for future policy benefit.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of interest expense recognized for liability for future policy benefit.
+ References
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| X                                                                                                                                                            |
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| X                                                                                                                                                |
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| X                                                                                                                                                 |
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