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Acquisitions - Summary of allocation of purchase price (Details) - US MidCorp and Entertainment - USD ($) $ in Millions |  | 3 Months Ended
--- | --- | ---
Aug. 01, 2024 | Jun. 30, 2025
Purchase price |  |  |
Business acquisition, cash paid |  | $ 450 |
Assets Acquired |  |  |
Cash and investments, at fair value |  | 2,332 |
Premiums receivable, net of commissions |  | 224 |
Other assets acquired |  | 175 |
Total assets acquired |  | 3,296 |
Liabilities Acquired |  |  |
Reserves for losses and loss adjustment expenses |  | 2,468 |
Unearned premiums |  | 636 |
Other liabilities acquired |  | 18 |
Total liabilities acquired |  | 3,122 |
Net assets acquired |  | 174 |
Goodwill |  | 276 |
Deferred tax asset, goodwill and intangibles |  | 565 |
Net deferred tax asset, loss reserves and unearned premium |  | 24 |
Goodwill, measurement period adjustment |  |  | $ 10
Reserves For Losses And Loss Adjustment Expenses |  |  |
Liabilities Acquired |  |  |
Loss reserves, fair value adjustment |  | 130 |
Distribution relationships |  |  |
Assets Acquired |  |  |
Intangible assets |  | $ 220 |
Useful life |  | 10 years |
Value of business acquired |  |  |
Assets Acquired |  |  |
Intangible assets |  | $ 165 |
Other intangible assets |  |  |
Assets Acquired |  |  |
Intangible assets | [1] | $ 180 |
Minimum | Value of business acquired |  |  |
Assets Acquired |  |  |
Useful life |  | 1 year |
Minimum | Other intangible assets |  |  |
Assets Acquired |  |  |
Useful life |  | 5 years |
Maximum | Value of business acquired |  |  |
Assets Acquired |  |  |
Useful life |  | 2 years |
Maximum | Other intangible assets |  |  |
Assets Acquired |  |  |
Useful life |  | 7 years |
[1] | Includes $130 million related to the net fair value adjustment to reserves for loss and loss adjustment expenses on August 1, 2024.

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