| **Reinsurance - Life Insurance Ceded Business (Detail) - USD ($) $ in Millions** | 3 Months Ended | 9 Months Ended |
|----------------------------------------------------------------------------------|----------------|----------------|
||
| **Reinsurance for Insurance Companies, by Product Segment**                      |           |           |   |   |
| Insurance losses and contract holders' benefits                                  | $ 1,418        | $ 1,072        | $ 3,766 | $ 2,990 |
| Life Insurance Segment                                                           |           |           |   |   |
| **Reinsurance for Insurance Companies, by Product Segment**                      |           |           |   |   |
| Direct earned premiums                                                           | 92             | 93             | 278 | 278 |
| Ceded earned premiums                                                            | (19)           | (20)           | (57) | (57) |
| Earned premiums                                                                  | 73             | 73             | 221 | 221 |
| Direct contract holders' benefits incurred                                       | 93             | 103            | 298 | 310 |
| Ceded contract holders' benefits incurred                                        | (23)           | (19)           | (76) | (61) |
| Insurance losses and contract holders' benefits                                  | $ 70           | $ 84           | $ 222 | $ 249 |

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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of earned premiums ceded to other entities.
+ References
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| - Definition
Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.
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| - Definition
Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred.
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| - Definition
Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred.
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| - Definition
Amount, after premiums ceded to other entities and premiums assumed by the entity, of life premiums earned.
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Amount of reduction of provision for policy benefits and costs incurred for policies ceded.
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