| **Revenue and Interest Recognized in Income (Details) - Life policy reserves: - USD ($) $ in Millions** | 3 Months Ended |
|---------------------------------------------------------------------------------------------------------|----------------|
||
| **Liability for Future Policy Benefit, Activity [Line Items]**                                          |           |   |
| Gross premiums                                                                                          | $ 85           | $ 81 |
| Interest accretion                                                                                      | 18             | 17 |
| Term Life Insurance                                                                                     |           |   |
| **Liability for Future Policy Benefit, Activity [Line Items]**                                          |           |   |
| Gross premiums                                                                                          | 73             | 69 |
| Interest accretion                                                                                      | 12             | 12 |
| Whole Life Insurance                                                                                    |           |   |
| **Liability for Future Policy Benefit, Activity [Line Items]**                                          |           |   |
| Gross premiums                                                                                          | 12             | 12 |
| Interest accretion                                                                                      | $ 6            | $ 5 |

| 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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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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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