Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt securities, available for sale, allowance for credit losses	$ 0.0	$ 1.1
Debt securities, available for sale, cost	4,617.0	5,143.8
Debt securities, trading, cost	140.9	187.3
Short-term investments, cost	48.2	95.3
Other long-term investments, cost	437.9	438.2
Related party investments at fair value	$ 220.1	$ 217.2
Common share, shares issued (in shares)	116,020,526	116,429,057
Common share, shares outstanding (in shares)	116,020,526	116,429,057
Series B preference shares
Preference shares, par value (in dollars per share)	$ 0.10	$ 0.10
Preference shares, shares authorized (in shares)	8,000,000	8,000,000
Preference shares, shares issued (in shares)	8,000,000	8,000,000

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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