Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended						6 Months Ended	9 Months Ended
	Jul. 30, 2023	Nov. 18, 2021	Nov. 15, 2021	Nov. 12, 2020	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Class of Stock [Line Items]
Common stock, par value (in dollars per share)								$ 0.01					$ 0.01
Convertible preferred stock, shares issued upon conversion (in shares)								2.1739					2.1739
Accelerated Share Repurchase, Volume-Weighted Average Stock Prices					$ 38.30
Common stock purchased										$ 0.0
Dividend declared (in dollars per share)				$ (0.30)
Dividends to common shareholders					$ 22.0	$ 22.0	$ 21.9	$ 21.6	$ 21.9	$ 20.1		$ 65.9	$ 63.6
Dividends paid on common stock												64.8	64.1
Dividends paid on convertible preferred stock (in dollars per share)												$ 0.0	$ 8.1
Preferred Stock, Dividends, Per Share, Cash Paid			$ 1.875
Common Stock
Class of Stock [Line Items]
Conversion of stock, shares issued (in shares)								4,700,000
Accelerated Share Repurchase Program
Class of Stock [Line Items]
Common stock purchased (in shares)		500,000				1,500,000					1,500,000
Treasury Stock, Value														$ 60.0
Subsequent Event
Class of Stock [Line Items]
Dividend declared (in dollars per share)	$ (0.30)
Common Stock
Class of Stock [Line Items]
Number of shares authorized to be acquired (shares)				7,500,000
Common stock purchased (in shares)										451,000
Common Stock | Share Repurchase Program
Class of Stock [Line Items]
Number of shares authorized to be acquired (shares)														75,000,000.0
Retained (Losses)/Earnings
Class of Stock [Line Items]
Dividends to common shareholders					0.0	$ 0.0	0.0	$ 21.6	$ 21.9	$ 20.1
Additional Paid-in Capital
Class of Stock [Line Items]
Common stock purchased					(15.0)					$ (15.0)
Dividends to common shareholders					$ 22.0	$ 22.0	$ 21.9