| **Other Intangible Assets (Summary of Other Intangible Assets) (Details) - USD ($) $ in Millions** | 12 Months Ended |        |
|----------------------------------------------------------------------------------------------------|-----------------|--------|
||
| **Schedule of Other Intangible Assets [Abstract]**                                                 |            |   |
| Finite-lived intangible assets:                                                                    | $ 16            | $ 18   |
| Indefinite-lived intangible assets:                                                                | 68              | 63     |
| Total other intangible assets                                                                      | 84              | 81     |
| Accumulated Amortization                                                                           | 13              | 14     |
| Syndicate capacity                                                                                 |            |   |
| **Schedule of Other Intangible Assets [Abstract]**                                                 |            |   |
| Indefinite-lived intangible assets:                                                                | 42              | 47     |
| Agency force                                                                                       |            |   |
| **Schedule of Other Intangible Assets [Abstract]**                                                 |            |   |
| Indefinite-lived intangible assets:                                                                | 16              | 16     |
| Insurance licenses                                                                                 |            |   |
| **Schedule of Other Intangible Assets [Abstract]**                                                 |            |   |
| Indefinite-lived intangible assets:                                                                | $ 10            | 0      |
| Trade name                                                                                         |            |   |
| **Schedule of Other Intangible Assets [Abstract]**                                                 |            |   |
| Economic Useful Life                                                                               | 8 years         |   |
| Finite-lived intangible assets:                                                                    | $ 6             | 7      |
| Accumulated Amortization                                                                           | $ 6             | 7      |
| Distribution channel                                                                               |            |   |
| **Schedule of Other Intangible Assets [Abstract]**                                                 |            |   |
| Economic Useful Life                                                                               | 15 years        |   |
| Finite-lived intangible assets:                                                                    | $ 10            | 11     |
| Accumulated Amortization                                                                           | $ 7             | $ 7    |

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| - Definition
Schedule of Other Intangible Assets [Abstract]
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| - Definition
Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
+ References
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| - Definition
Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
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| - Definition
Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.
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| - Definition
Amount before accumulated amortization of intangible assets, excluding goodwill.
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