Shareholders' Equity - Shares Repurchased (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended							9 Months Ended		10 Months Ended	12 Months Ended
	Nov. 07, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Nov. 07, 2023	Dec. 31, 2022	Nov. 01, 2023
Equity, Class of Treasury Stock [Line Items]
Repurchases of common stock									$ 90.0	$ 400.0
Common Shares
Equity, Class of Treasury Stock [Line Items]
Shares repurchased (in shares)		1,065,902	453,942	36,369	1,713,416	1,790,395	2,605,947	2,738,223				8,847,981
Repurchases of common stock		$ 64.0	$ 24.0	$ 2.0	$ 100.0	$ 97.0	$ 151.0	$ 155.0				$ 503.0
Average price paid per share (in dollars per share)		$ 59.67	$ 53.08	$ 62.23	$ 58.34	$ 53.77	$ 58.03	$ 56.62				$ 56.79
Common Shares | Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Repurchased additional authorized amount													$ 300.0
Remaining capacity of shares repurchase program	$ 372.0										$ 372.0
Shares repurchased (in shares)	682,676										2,238,889
Repurchases of common stock	$ 42.0										$ 132.0
Average price paid per share (in dollars per share)	$ 61.17										$ 58.83