CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Net sales	$ 4,620.0	$ 4,923.1
Cost of goods sold	3,861.2	4,157.1
Gross profit	758.8	766.0
Selling, general and administrative expense excluding intangible amortization	527.1	479.1
Selling, general and administrative intangible amortization expense	82.0	86.6
Restructuring and other costs, net	65.5	32.1
Operating profit	84.2	168.2
Interest expense, net	(101.4)	(97.3)
Pension and other postretirement non-service income (cost)	0.2	(5.0)
Other (expense) income, net	(4.7)	25.2
Equity in income (loss) of unconsolidated entities	4.2	(36.0)
Gain on sale of RTS and Chattanooga	0.5
(Loss) income before income taxes	(17.0)	55.1
Income tax expense	(5.7)	(8.3)
Consolidated net (loss) income	(22.7)	46.8
Less: Net loss (income) attributable to noncontrolling interests	0.3	(1.5)
Net (loss) income attributable to common stockholders	$ (22.4)	$ 45.3
Basic (loss) earnings per share attributable to common stockholders	$ (0.09)	$ 0.18
Diluted (loss) earnings per share attributable to common stockholders	$ (0.09)	$ 0.18
Basic weighted average shares outstanding	257.0	254.7
Diluted weighted average shares outstanding	257.0	256.7