CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
Net sales	$ 5,277.6	$ 5,382.1	$ 10,200.7	$ 10,334.3
Cost of goods sold	4,357.3	4,378.4	8,515.2	8,534.0
Gross profit	920.3	1,003.7	1,685.5	1,800.3
Selling, general and administrative expense excluding intangible amortization	498.9	493.1	978.0	946.0
Selling, general and administrative intangible amortization expense	86.2	88.1	172.8	176.1
(Gain) loss on disposal of assets	(8.6)	2.5	(10.3)	(11.4)
Multiemployer pension withdrawal income				(3.3)
Restructuring and other costs	444.7	363.4	477.7	365.7
Goodwill impairment	1,893.0		1,893.0
Operating (loss) profit	(1,993.9)	56.6	(1,825.7)	327.2
Interest expense, net	(108.4)	(72.5)	(205.7)	(159.2)
Loss on extinguishment of debt		(8.2)		(8.2)
Pension and other postretirement non-service (cost) income	(6.0)	39.7	(11.0)	79.6
Other (expense) income, net	(17.8)	6.3	7.4	6.5
Equity in income (loss) of unconsolidated entities	4.5	20.6	(31.5)	39.0
(Loss) income before income taxes	(2,121.6)	42.5	(2,066.5)	284.9
Income tax benefit (expense)	116.8	(1.8)	108.5	(60.4)
Consolidated net (loss) income	(2,004.8)	40.7	(1,958.0)	224.5
Less: Net income attributable to noncontrolling interests	(1.3)	(0.8)	(2.8)	(2.3)
Net (loss) income attributable to common stockholders	$ (2,006.1)	$ 39.9	$ (1,960.8)	$ 222.2
Basic (loss) earnings per share attributable to common stockholders	$ (7.85)	$ 0.15	$ (7.68)	$ 0.84
Diluted (loss) earnings per share attributable to common stockholders	$ (7.85)	$ 0.15	$ (7.68)	$ 0.83
Basic weighted average shares outstanding	255.6	263.4	255.2	264.0
Diluted weighted average shares outstanding	255.6	265.3	255.2	266.1