Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Total investments	$ 4,011.1	$ 3,481.2
Mortgage loans	171.6	144.8
Unfunded commitments	93.7	93.4
Other Invested Assets
Related Party Transaction [Line Items]
Total investments	344.4	$ 311.0
Related Party
Related Party Transaction [Line Items]
Total investments	48.4
Mortgage loans	27.3
Unfunded commitments	40.7
Investment management fees	2.3
Related Party \| Other Invested Assets
Related Party Transaction [Line Items]
Total investments	$ 21.1

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

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Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Sum of the carrying amounts as of the balance sheet date of all investments.

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