Prior Year Claims and Claims Adjustment Expense, Percentage

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- Definition

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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- Definition

Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred and costs incurred in the claim settlement process.

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Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs.

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Reserve for Property and Casualty Insurance Claims and Claims Expense - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Increase (decrease) in claims and claims expense
Prior years	$ (641)	$ (370)	$ (1,645)	$ (621)
Personal auto injury coverage \| Favorable Severity Development
Increase (decrease) in claims and claims expense
Prior years	$ 597		$ 1,270
Personal auto injury coverage \| Favorable Severity Development \| Short-Duration Insurance Contract, Accident Year 2025
Increase (decrease) in claims and claims expense
Percentage of claims	51.00%		30.00%
Personal auto injury coverage \| Favorable Severity Development \| Short-Duration Insurance Contract, Accident Year 2023 And 2024
Increase (decrease) in claims and claims expense
Percentage of claims	33.00%		51.00%
Personal other auto coverages \| Favorable Severity Development
Increase (decrease) in claims and claims expense
Prior years	$ 42		$ 205
Catastrophe
Increase (decrease) in claims and claims expense
Losses from catastrophes, net of recoveries			2,960	4,190
Prior years	$ 51	$ 6	$ 63	$ (10)