Earnings per Share - Schedule of Calculation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Calculation of basic earnings per share:
Net income applicable to common stock	$ 78.2	$ 26.0	$ 591.2	$ 77.5
Weighted-average common shares outstanding - basic (in shares)	152.8	164.8	153.0	166.5
Basic earnings per share (in dollars per share)	$ 0.51	$ 0.16	$ 3.86	$ 0.47
Calculation of diluted earnings per share:
Net income applicable to common stock	$ 78.2	$ 26.0	$ 591.2	$ 77.5
Convertible Notes	1.8	1.8	3.6	3.7
Diluted income applicable to common stock	$ 80.0	$ 27.8	$ 594.8	$ 81.2
Weighted average common shares outstanding - diluted (in shares)	167.9	180.2	168.2	182.3
Diluted earnings per share (in dollars per share)	$ 0.48	$ 0.15	$ 3.54	$ 0.45
Effective tax rate	30.70%	68.30%	25.50%	57.20%
Convertible Notes
Calculation of diluted earnings per share:
Effective tax rate	21.00%	21.00%	21.00%	21.00%
Common Stock, Non-Exchangeable
Calculation of basic earnings per share:
Weighted-average common shares outstanding - basic (in shares)	152.2	164.2	152.4	165.9
Common Stock, Exchangeable
Calculation of basic earnings per share:
Weighted-average common shares outstanding - basic (in shares)	0.6	0.6	0.6	0.6