Shareholders' Equity and Earnings (Loss) Per Common Share - Common Shares Repurchased (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended		28 Months Ended
	Jul. 31, 2022	Jun. 30, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Mar. 31, 2020
Sale of stock
Authorized value of shares for repurchase		$ 1,000.0	$ 1,000.0		$ 1,000.0	$ 500.0
Additional shares authorized		$ 500.0	$ 500.0		$ 500.0
Repurchase and retired common shares		8,500,000	11,800,000	619,749	21,000,000.0
Repurchase and retired common shares, Value		$ 213.9	$ 307.0	$ 19.2	$ 569.5
Average purchase price		$ 25.15	$ 25.91	$ 30.96	$ 27.12
Subsequent Event
Sale of stock
Repurchase and retired common shares	1,500,000
Repurchase and retired common shares, Value	$ 36.0
Average purchase price	$ 23.92