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.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 9E
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Amount, after reinsurance, of paid claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

+ References

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- Definition

Undiscounted amount, after reinsurance, of incurred-but-not-reported (IBNR) liabilities plus expected development on reported claims, for claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

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- Definition

Undiscounted amount, after reinsurance, of incurred claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

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- Definition

Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

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- Definition

Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts for accident years not separately presented in claim development information. Excludes unallocated claim adjustment expense.

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- Definition

Cumulative number of reported claims for short-duration insurance contracts.

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Property Casualty Loss and Loss Expense - Claims Development - Homeowner (Details) reported_claim in Thousands, $ in Millions	Dec. 31, 2024 USD ($) reported_claim	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Claims Development
Incurred losses and ALAE, net of reinsurance for the years ended December 31,	$ 3,589
Liabilities for loss and ALAE, net of reinsurance	9,416
Homeowner \| Personal Insurance
Claims Development
Incurred losses and ALAE, net of reinsurance for the years ended December 31,	2,946
Cumulative paid losses and ALAE, net of reinsurance	2,540
All outstanding liabilities before, net of reinsurance	8
Liabilities for loss and ALAE, net of reinsurance	414
2020 \| Homeowner \| Personal Insurance
Claims Development
Incurred losses and ALAE, net of reinsurance for the years ended December 31,	471	$ 471	$ 470	$ 475	$ 497
Total of incurred but not reported liabilities plus expected development on reported losses	$ 2
Cumulative number of reported claims \| reported_claim	23
Cumulative paid losses and ALAE, net of reinsurance	$ 468	464	453	434	$ 326
2021 \| Homeowner \| Personal Insurance
Claims Development
Incurred losses and ALAE, net of reinsurance for the years ended December 31,	440	440	449	495
Total of incurred but not reported liabilities plus expected development on reported losses	$ 3
Cumulative number of reported claims \| reported_claim	19
Cumulative paid losses and ALAE, net of reinsurance	$ 431	424	405	$ 285
2022 \| Homeowner \| Personal Insurance
Claims Development
Incurred losses and ALAE, net of reinsurance for the years ended December 31,	500	505	552
Total of incurred but not reported liabilities plus expected development on reported losses	$ 7
Cumulative number of reported claims \| reported_claim	20
Cumulative paid losses and ALAE, net of reinsurance	$ 481	461	$ 299
2023 \| Homeowner \| Personal Insurance
Claims Development
Incurred losses and ALAE, net of reinsurance for the years ended December 31,	693	742
Total of incurred but not reported liabilities plus expected development on reported losses	$ 20
Cumulative number of reported claims \| reported_claim	24
Cumulative paid losses and ALAE, net of reinsurance	$ 637	$ 468
2024 \| Homeowner \| Personal Insurance
Claims Development
Incurred losses and ALAE, net of reinsurance for the years ended December 31,	842
Total of incurred but not reported liabilities plus expected development on reported losses	$ 144
Cumulative number of reported claims \| reported_claim	22
Cumulative paid losses and ALAE, net of reinsurance	$ 523