Insurance subsidiaries Disclosure - Narrative (Detail) - USD ($) $ in Billions |
Dec. 31, 2025 |
Dec. 31, 2024 |
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| Statutory Accounting Practices [Line Items] | ||
| Investments in fixed maturity and equity securities and short-term investments on deposit with U.S. state insurance authorities | $ 5.5 | $ 5.6 |
| United States Based Property and Casualty Insurance Subsidiaries [Member] | ||
| Statutory Accounting Practices [Line Items] | ||
| Statutory shareholders' equity | 333.0 | $ 310.0 |
| Principal Insurance Subsidiaries [Member] | ||
| Statutory Accounting Practices [Line Items] | ||
| Amount available for payment of dividends without prior regulatory approval during 2026 | $ 33.0 |
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- Definition Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of dividends available for payment after computation of statutory restrictions on capital surplus. No definition available.
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- Definition The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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