Summary of Significant Accounting Policies - Summary of Earnings Per Share, Weighted Average Common Shares and Potential Common Shares Outstanding (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Loss from continuing operations	$ (339.0)	$ (479.0)	$ (63.2)	$ 29.9	$ (1,060.5)	$ 31.6	$ (50.2)	$ (105.6)	$ (851.3)	$ (1,184.7)	$ (350.0)
Loss from discontinued operations, net of tax									(599.6)	(102.2)	(112.6)
Net loss	(525.2)	(828.7)	(100.4)	3.4	(1,108.9)	22.9	(61.0)	(139.9)	(1,450.9)	(1,286.9)	(462.6)
Dividends on Series A convertible preferred stock									(61.8)	(59.0)	(57.3)
Net loss attributable to common stockholders	$ (541.1)	$ (844.2)	$ (115.7)	$ (11.7)	$ (1,123.8)	$ 8.0	$ (75.7)	$ (154.4)	$ (1,512.7)	$ (1,345.9)	$ (519.9)
Denominator:
Weighted average common shares outstanding - basic									210.9	207.4	203.6
Dilutive effect of as-if converted Series A convertible preferred stock									0.0	0.0	0.0
Dilutive effect of equity-based awards									0.0	0.0	0.0
Weighted average common shares outstanding - diluted									210.9	207.4	203.6
Basic:
Loss from continuing operations per share	$ (1.67)	$ (2.33)	$ (0.37)	$ 0.07	$ (5.16)	$ 0.08	$ (0.31)	$ (0.58)	$ (4.33)	$ (6)	$ (2)
Loss from discontinued operations per share									(2.84)	(0.49)	(0.55)
Loss per share									(7.17)	(6.49)	(2.55)
Diluted:
Loss from continuing operations per share	$ (1.67)	$ (2.33)	$ (0.37)	$ 0.07	$ (5.16)	$ 0.08	$ (0.31)	$ (0.58)	(4.33)	(6)	(2)
Loss from discontinued operations per share									(2.84)	(0.49)	(0.55)
Loss per share									$ (7.17)	$ (6.49)	$ (2.55)