STATEMENT OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
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| Statement of Comprehensive Income [Abstract] | ||||
| Change in Net Unrealized Loss on Securities, Tax Expense (Benefit) | $ 38.6 | $ 22.0 | $ (77.5) | $ 132.2 |
| OCI, Liability for Future Policy Benefit, Gain (Loss), after REclassification Adjustment, Tax | (59.9) | 10.9 | 66.0 | (31.7) |
| Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax | 0.8 | (15.9) | (0.2) | (4.2) |
| Change in Foreign Currency Translation Adjustment, Tax Expense (Benefit) | (0.3) | (0.4) | (0.4) | (0.2) |
| Change in Unrecognized Pension and Postretirement Benefit costs, Tax Expense | $ (0.5) | $ 0.5 | $ (1.5) | $ 0.7 |
| X | ||||||||||
- Definition Amount, after reclassification adjustment, of tax expense (benefit) for unrealized gain (loss) from (increase) decrease in liability for future policy benefit from change in discount rate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount, after adjustment, of tax expense (benefit) for unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and tax expense (benefit) for unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount, after reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of tax expense (benefit), after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount, after reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income of defined benefit plan. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- References No definition available.
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