Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Statement of Comprehensive Income [Abstract]
Net derivative (losses) gains and other costs arising during the period, net of tax (benefit) expense	$ (0.7)	$ 0.8	$ 1.3	$ 0.0
Reclassification of (gains) into net income (loss), net of tax (expense)	$ (0.3)	$ (0.8)	$ (1.1)	$ (2.3)