| **Reinsurance Reinsurance (Written Consolidated Property Casualty Insurance Premiums On Assumed and Ceded Business) (Details) - USD ($) $ in Millions** | 12 Months Ended |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]**                                                                       |            |   |   |
| Direct Premiums Earned                                                                                                                                  | $ 5,251         | $ 5,052 | $ 4,857 |
| Assumed Premiums Earned                                                                                                                                 | 149             | 132 | 77 |
| Ceded Premiums Earned                                                                                                                                   | 230             | 230 | 224 |
| Insurance losses and contract holders' benefits                                                                                                         | 3,490           | 3,390 | 3,107 |
| Consolidated Property and Casualty Insurance Entity                                                                                                     |            |   |   |
| **Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]**                                                                       |            |   |   |
| Direct Premiums Written                                                                                                                                 | 5,018           | 4,854 | 4,646 |
| Assumed Premiums Written                                                                                                                                | 173             | 125 | 103 |
| Ceded Premiums Written                                                                                                                                  | (161)           | (139) | (169) |
| Premiums Written, Net, Property and Casualty                                                                                                            | 5,030           | 4,840 | 4,580 |
| Direct Premiums Earned                                                                                                                                  | 4,931           | 4,752 | 4,567 |
| Assumed Premiums Earned                                                                                                                                 | 149             | 132 | 77 |
| Ceded Premiums Earned                                                                                                                                   | (160)           | (162) | (162) |
| Premiums Earned, Net, Property and Casualty                                                                                                             | 4,920           | 4,722 | 4,482 |
| Policyholder Benefits and Claims Incurred, Direct                                                                                                       | 3,188           | 2,961 | 2,874 |
| Policyholder Benefits and Claims Incurred, Assumed                                                                                                      | 125             | 113 | 43 |
| Policyholder Benefits and Claims Incurred, Ceded                                                                                                        | (90)            | 64 | (56) |
| Insurance losses and contract holders' benefits                                                                                                         | $ 3,223         | $ 3,138 | $ 2,861 |

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Amount, after premiums ceded to other entities and premiums assumed by the entity, of property and casualty premiums written.
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Amount of earned premiums ceded to other entities.
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Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.
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Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred.
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Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred.
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Amount, after premiums ceded to other entities and premiums assumed by the entity, of property and casualty premiums earned.
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Amount of policy benefits and costs incurred for policies assumed.
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Amount of reduction of provision for policy benefits and costs incurred for policies ceded.
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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No definition available.
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