| **Future Policy Benefit Reserves - Earned Premiums and Interest Expense (Details) - USD ($) $ in Millions** | 3 Months Ended | 6 Months Ended |
|-------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Insurance [Abstract]**                                                                                    |           |           |   |   |
| Earned premiums                                                                                             | $ 113          | $ 118          | $ 228 | $ 238 |
| Interest expense                                                                                            | $ 189          | $ 189          | $ 379 | $ 377 |

| X                                                                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
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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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