| **Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions** | 3 Months Ended | 6 Months Ended |
|------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]**                                                    |           |           |   |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | $ 660          | $ 618          | $ 637 | $ 616 |
| Capitalized deferred policy acquisition costs                                                                                | 249            | 230            | 488 | 452 |
| Deferred Policy Acquisition Cost, Amortization Expense                                                                       | (229)          | (214)          | (443) | (426) |
| Deferred Policy Acquisition Cost, Amortization Expense, Other                                                                | (2)            | (10)           | (4) | (18) |
| Deferred policy acquisition costs asset, end of period                                                                       | 678            | 624            | 678 | 624 |
| Life Insurance Product Line [Member]                                                                                         |           |           |   |   |
| **Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]**                                                    |           |           |   |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | 232            | 221            | 229 | 228 |
| Capitalized deferred policy acquisition costs                                                                                | 12             | 12             | 25 | 24 |
| Deferred Policy Acquisition Cost, Amortization Expense                                                                       | (12)           | (11)           | (20) | (22) |
| Deferred Policy Acquisition Cost, Amortization Expense, Other                                                                | (2)            | (10)           | (4) | (18) |
| Deferred policy acquisition costs asset, end of period                                                                       | 230            | 212            | 230 | 212 |
| Consolidated Property and Casualty Insurance Entity                                                                          |           |           |   |   |
| **Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]**                                                    |           |           |   |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | 428            | 397            | 408 | 388 |
| Capitalized deferred policy acquisition costs                                                                                | 237            | 218            | 463 | 428 |
| Deferred Policy Acquisition Cost, Amortization Expense                                                                       | (217)          | (203)          | (423) | (404) |
| Deferred policy acquisition costs asset, end of period                                                                       | $ 448          | $ 412          | $ 448 | $ 412 |

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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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