| **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**                                                                   |           |           |   |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | $ 827          | $ 751          | $ 774 | $ 738 |
| Capitalized deferred policy acquisition costs                                                                                | 306            | 295            | 601 | 565 |
| Amortized deferred policy acquisition costs                                                                                  | (276)          | (251)          | (541) | (497) |
| Shadow deferred policy acquisition costs                                                                                     | (23)           | (9)            | 0 | (20) |
| Deferred policy acquisition costs asset, end of period                                                                       | 834            | 786            | 834 | 786 |
| Consolidated Property and Casualty Insurance Entity                                                                          |           |           |   |   |
| **Movement Analysis of Deferred Policy Acquisition Costs**                                                                   |           |           |   |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | 536            | 485            | 512 | 464 |
| Capitalized deferred policy acquisition costs                                                                                | 292            | 280            | 572 | 534 |
| Amortized deferred policy acquisition costs                                                                                  | (261)          | (239)          | (517) | (472) |
| Deferred policy acquisition costs asset, end of period                                                                       | 567            | 526            | 567 | 526 |
| Life Insurance Segment                                                                                                       |           |           |   |   |
| **Movement Analysis of Deferred Policy Acquisition Costs**                                                                   |           |           |   |   |
| Deferred policy acquisition costs asset, beginning of period                                                                 | 291            | 266            | 262 | 274 |
| Capitalized deferred policy acquisition costs                                                                                | 14             | 15             | 29 | 31 |
| Amortized deferred policy acquisition costs                                                                                  | (15)           | (12)           | (24) | (25) |
| Shadow deferred policy acquisition costs                                                                                     | (23)           | (9)            | 0 | (20) |
| Deferred policy acquisition costs asset, end of period                                                                       | $ 267          | $ 260          | $ 267 | $ 260 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of amortization expense (reversal of expense) for 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
Amount of deferred policy acquisition cost capitalized on contract remaining in force.
+ References
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| - Definition
Amount of deferred policy acquisition cost capitalized.
+ 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.
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No definition available.
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