| **Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions** | 3 Months Ended |
|------------------------------------------------------------------------------------------------------------------------------|----------------|
||
| **Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]**                                                    |           |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | $ 616          | $ 578 |
| Capitalized deferred policy acquisition costs                                                                                | 222            | 207 |
| Deferred Policy Acquisition Cost, Amortization Expense                                                                       | (212)          | (209) |
| Deferred Policy Acquisition Cost, Amortization Expense, Other                                                                | (8)            | (5) |
| Deferred policy acquisition costs asset, end of period                                                                       | 618            | 571 |
| Life Insurance Product Line [Member]                                                                                         |           |   |
| **Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]**                                                    |           |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | 228            | 199 |
| Capitalized deferred policy acquisition costs                                                                                | 12             | 11 |
| Deferred Policy Acquisition Cost, Amortization Expense                                                                       | (11)           | (11) |
| Deferred Policy Acquisition Cost, Amortization Expense, Other                                                                | (8)            | (5) |
| Deferred policy acquisition costs asset, end of period                                                                       | 221            | 194 |
| Consolidated Property and Casualty Insurance Entity                                                                          |           |   |
| **Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]**                                                    |           |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | 388            | 379 |
| Capitalized deferred policy acquisition costs                                                                                | 210            | 196 |
| Deferred Policy Acquisition Cost, Amortization Expense                                                                       | (201)          | (198) |
| Deferred policy acquisition costs asset, end of period                                                                       | $ 397          | $ 377 |

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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of expense related to deferred policy acquisition costs.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of other increase (decrease) to amortization expense of deferred policy acquisition cost (DAC).
+ References
No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Net amount of deferred policy acquisition costs capitalized on contracts remaining in force as of the balance sheet date.
+ References
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total amount of policy acquisition costs capitalized during the income statement period.
+ References
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| - Definition
A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.
+ References
No definition available.
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