Net Income (Loss) Per Share - Components and Calculation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended								6 Months Ended
		Jun. 30, 2022		Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021		Mar. 31, 2021	Jun. 30, 2022		Jun. 30, 2021
Numerator:
Net income (loss) from continuing operations		$ 174.5		$ 55.8	$ 68.1	$ 104.5	$ 79.8		$ (10.5)	$ 230.3		$ 69.3
Dividends on Preferred Stock		(6.0)					(6.0)			(12.0)		(12.0)
Undistributed income from continuing operations allocated to participating securities		(20.9)					(9.0)			(26.8)		(6.9)
Net income (loss) from continuing operations attributable to common stockholders - Basic		147.6					64.8			191.5		50.4
Net income (loss) from continuing operations attributable to common stockholders - Diluted		147.6					64.8			191.5		50.4
Net income (loss) from discontinued operations – Basic	[1]	0.0					(3.3)			0.0		0.9
Undistributed income from discontinued operations allocated to participating securities, Basic		0.0					0.4			0.0		(0.2)
Undistributed income from discontinued operations allocated to participating securities, Diluted		0.0					0.4			0.0		(0.2)
Net income (loss) from discontinued operations attributable to common stockholders - Basic		0.0					(2.9)			0.0		0.7
Net income (loss) from discontinued operations attributable to common stockholders - Diluted		0.0					(2.9)			0.0		0.7
Net income (loss) attributable to common stockholders – Basic and Diluted		$ 147.6					$ 61.9			$ 191.5		$ 51.1
Denominator:
Weighted-average common shares outstanding - Basic (in shares)	[2]	68.1					69.9			69.1		69.8
Effect of common share equivalents (in shares)		1.4					1.4			1.3		1.2
Weighted-average common shares outstanding - Diluted (in shares)	[2]	69.5					71.3			70.4		71.0
Net income (loss) per share:
Basic - Continuing operations (usd per share)		$ 2.17	[2]	$ 0.62	$ 0.78	$ 1.23	$ 0.93	[2]	$ (0.24)	$ 2.77	[2]	$ 0.72	[2]
Basic - Discontinued operations ( usd per share)	[2]	0					(0.04)			0		0.01
Basic net income (loss) per share ( usd per share)		2.17	[2]	0.62	0.78	1.24	0.89	[2]	(0.18)	2.77	[2]	0.73	[2]
Diluted - Continuing operations (usd per share)		2.12	[2]	0.61	0.76	1.21	0.91	[2]	(0.24)	2.72	[2]	0.71	[2]
Diluted - Discontinued operations ( usd per share)	[2]	0					(0.04)			0		0.01
Diluted net income (loss) per share ( usd per share)		$ 2.12	[2]	$ 0.61	$ 0.76	$ 1.22	$ 0.87	[2]	$ (0.18)	$ 2.72	[2]	$ 0.72	[2]

[1] See Note 4 for additional information.

[2] See Note 6 for detailed calculations and further discussion.