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Share Transactions - Share repurchases (Details) - Authorized Share Repurchase Program - Common shares - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Class of Stock [Line Items]
Cumulative number of shares acquired since inception of share repurchase program	437,900,000
Aggregate purchase price of shares acquired since inception of share repurchase program	$ 6,300.0
Treasury stock, shares acquired (shares)	4,100,000	0
Aggregate cost of shares repurchased	$ 359.7
Remaining authorized repurchase amount	$ 637.1

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