CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2021
Income Statement [Abstract]
Net sales		$ 1,791.7	$ 9,657.9	$ 8,282.0	$ 7,737.3
Cost of sales		1,596.4	7,977.1	7,227.6	6,469.1
Gross income		195.3	1,680.8	1,054.4	1,268.2
Operating expenses:
Selling, general and administrative		150.9	810.4	662.8	666.5
Amortization of purchased intangibles		2.8	32.8	11.6	9.6
Intangible asset impairment				7.7
Total operating expenses		153.7	843.2	682.1	676.1
Operating income		41.6	837.6	372.3	592.1
Other income (expense):
Interest expense		(12.5)	(68.6)	(53.4)	(48.2)
Interest income		0.7	14.8	9.5	3.5
Miscellaneous, net	[1]	(5.6)	13.8	(52.8)	(2.1)
Income before income taxes and earnings (losses) of unconsolidated affiliates		24.2	797.6	275.6	545.3
Provision for income taxes		1.2	190.0	97.5	36.4
Income before earnings (losses) of unconsolidated affiliates		23.0	607.6	178.1	508.9
Equity in earnings (losses) of unconsolidated affiliates		1.2	(9.6)	(4.2)
Net income		$ 24.2	$ 598.0	$ 173.9	$ 508.9
Earnings per share:
Basic		$ 0.36	$ 9.15	$ 2.65	$ 7.43
Diluted		$ 0.36	$ 9.08	$ 2.63	$ 7.35

[1] Results for 2023 include a gain of $4.7 million on the settlement of a claim with the Company's pension advisor. Results for 2022 include a $33.6 million charge from the settlement of a frozen pension plan.