Investment Securities - Rollforward of Fair Value Measurements by Level (Details) - Other long-term investments - USD ($) $ in Millions |
9 Months Ended | |
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Sep. 30, 2026 |
Sep. 30, 2025 |
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| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
| Beginning balance | $ 1,814.4 | $ 1,262.7 |
| Net realized and unrealized gains | 144.6 | 105.7 |
| Purchases and contributions | 180.2 | 119.6 |
| Effect of Distinguished Transaction | 0.0 | (7.1) |
| Sales and distributions | (110.6) | (1.7) |
| Transfers in | 0.0 | 0.0 |
| Transfers out | 0.0 | 0.0 |
| Ending balance | $ 2,028.6 | $ 1,479.2 |
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Details
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