Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net income (loss) attributable to common stockholders	$ 15.5	$ (2,006.1)	$ (6.9)	$ (1,960.8)
Basic weighted average shares outstanding	258.0	255.6	257.5	255.2
Effect of dilutive stock options and non-participating securities	1.3
Diluted weighted average shares outstanding	259.3	255.6	257.5	255.2
Basic earnings (loss) per share attributable to common stockholders	$ 0.06	$ (7.85)	$ (0.03)	$ (7.68)
Diluted earnings (loss) per share attributable to common stockholders	$ 0.06	$ (7.85)	$ (0.03)	$ (7.68)