| **Commitments And Contingent Liabilities**              | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              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| **Commitments and Contingencies Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  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| Commitments And Contingent Liabilities                  | Commitments and Contingent LiabilitiesThe company, through its insurance subsidiaries, is involved in claims litigation arising in the ordinary course of conducting its business, both as a liability insurer defending or providing indemnity for third-party claims brought against insureds and as an insurer defending coverage claims brought against it. The company accounts for such activity through the establishment of unpaid loss and loss expense reserves. Subject to the uncertainties discussed in Note 4, Property Casualty Loss and Loss Expenses, and in the discussion in the balance of this Note, we believe that the ultimate liability, if any, with respect to such ordinary-course claims litigation, after consideration of provisions made for potential losses, costs of defense, and reinsurance recoveries, is immaterial to our consolidated financial position, results of operations and cash flows.Beginning in April 2020, like many companies in the property casualty insurance industry, the company’s property casualty subsidiaries, were named as defendants in lawsuits seeking insurance coverage under commercial property insurance policies issued by the company for alleged losses resulting from the shutdown or suspension of their businesses due to the COVID-19 pandemic. Although the allegations vary, the plaintiffs generally seek a declaration of insurance coverage, damages for breach of contract in unspecified amounts for claim denials, interest and attorney fees. Some of the lawsuits also allege that the insurance claims were denied in bad faith or otherwise in violation of state laws and seek extra-contractual or punitive damages.  The company denies the allegations in these lawsuits and intends to continue to vigorously defend the lawsuits.  The company maintains that it has no coverage obligations with respect to these lawsuits for business income allegedly lost by the plaintiffs due to the COVID-19 pandemic based on the terms of the applicable insurance policies. Although the policy terms vary, in general, the claims at issue in these lawsuits were denied because the policyholder identified no direct physical loss or damage to property at the insured premises, and the governmental orders that led to the complete or partial shutdown of the business were not due to the existence of any direct physical loss or damage to property in the immediate vicinity of the insured premises and did not prohibit access to the insured premises, as required by the terms of the insurance policies. Depending on the individual policy, additional policy terms and conditions may also prohibit coverage, such as exclusions for pollutants, ordinance or law, loss of use, and acts or decisions. The company’s standard commercial property insurance policies generally did not contain a specific virus exclusion.In addition to the inherent difficulty in predicting litigation outcomes, the COVID-19 pandemic business income coverage lawsuits present a number of uncertainties and contingencies that are not yet known, including how many policyholders will ultimately file claims, the number of lawsuits that will be filed, the extent to which any class may be certified, and the size and scope of any such classes. The legal theories advanced by plaintiffs vary by case as do the state laws that govern the policy interpretation. These lawsuits are at various stages of litigation, including several that continue to be amended; many that have been dismissed; several that may be refiled; and others that have been dismissed by trial courts and appealed. While appellate decisions issued to date generally have been favorable for the insurance industry and the company, many remain to be decided. In some jurisdictions, many cases have been stayed pending appellate decisions in their state or federal circuit. Accordingly, little discovery has occurred on pending cases. In addition, business income calculations depend upon a wide range of factors that are particular to the circumstances of each individual policyholder and, here, virtually none of the plaintiffs have submitted proofs of loss or otherwise quantified or factually supported any allegedly covered loss. Moreover, the company’s experience shows that demands for damages often bear little relation to a reasonable estimate of potential loss. Accordingly, management cannot now reasonably estimate the possible loss or range of loss, if any. Nonetheless, given the number of claims and potential claims, the indeterminate amounts sought, and the inherent unpredictability of litigation, it is possible that adverse outcomes, if any, in the aggregate could have a material adverse effect on the company’s consolidated financial position, results of operations and cash flows.The company and its subsidiaries also are occasionally involved in other legal and regulatory proceedings, some of which assert claims for substantial amounts. These actions include, among others, putative class actions seeking certification of state or national classes. Such proceedings have alleged, for example, improper depreciation of labor costs in repair estimates. The company’s insurance subsidiaries also are occasionally parties to individual actions in which extra-contractual damages, punitive damages or penalties are sought, such as claims alleging bad faith handling of insurance claims or writing unauthorized coverage or claims alleging discrimination by former or current associates.On a quarterly basis, we review these outstanding matters. Under current accounting guidance, we establish accruals when it is probable that a loss has been incurred and we can reasonably estimate its potential exposure.  The company accounts for such probable and estimable losses, if any, through the establishment of legal expense reserves. Based on our quarterly review, we believe that our accruals for probable and estimable losses are reasonable and that the amounts accrued do not have a material effect on our consolidated financial position, results of operations and cash flows. However, if any one or more of these matters results in a judgment against us or settlement for an amount that is significantly greater than the amount accrued, the resulting liability could have a material effect on the company’s consolidated financial position, results of operations and cash flows. Based on our most recent review, our estimate for any other matters for which the risk of loss is not probable, but more than remote, is immaterial. |

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No definition available.
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| - Definition
The entire disclosure for commitments and contingencies.
+ References
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