| **Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions** | Dec. 31, 2022 | Dec. 31, 2021 |
|--------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Deferred tax assets:**                                                                               |          |          |
| Unearned premiums                                                                                      | $ 148         | $ 131         |
| Loss and loss expense reserves                                                                         | 106           | 92            |
| Net operating loss on international earnings                                                           | 28            | 34            |
| Deferred international earnings                                                                        | 16            | 31            |
| Other                                                                                                  | 55            | 50            |
| Deferred tax assets before valuation allowance                                                         | 353           | 338           |
| Valuation allowance for international operations                                                       | 31            | 53            |
| Deferred tax assets net of valuation allowance                                                         | 322           | 285           |
| **Deferred tax liabilities:**                                                                          |          |          |
| Investment gains and other, net                                                                        | 992           | 1,684         |
| Deferred acquisition costs                                                                             | 171           | 155           |
| Life policy reserves                                                                                   | 112           | 116           |
| Investments                                                                                            | 31            | 38            |
| Other                                                                                                  | 61            | 36            |
| Total gross deferred tax liabilities                                                                   | 1,367         | 2,029         |
| Net deferred income tax liability                                                                      | $ 1,045       | $ 1,744       |

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| - Definition
Amount of deferred tax liability attributable to taxable temporary differences.
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.
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| - Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign operating loss carryforwards.
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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from loss reserves other than estimated credit losses.
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| - Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from the unearned premiums reserve.
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| - Definition
Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.
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| - Definition
Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.
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| - Definition
The amount as of the balance sheet date of the estimated future tax effects attributable to policy acquisition costs being expensed for tax purposes but capitalized in conformity with generally accepted accounting principles, which will reverse in future periods when amortization of such capitalized costs cannot be deducted for tax purposes.
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Amount of deferred tax liability attributable to taxable temporary differences classified as other.
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