CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Operating Activities
Consolidated net income (loss)	$ 52.1	$ (202.0)	$ 576.7
Total income from discontinued operations	0.0	(2.2)	(462.6)
Adjustments to reconcile income (loss) from continuing operations to cash provided by operating activities:
Depreciation and amortization	138.5	158.0	125.6
Impairment charges	83.5	265.0	0.0
Gain on sale of property, plant, and equipment	0.0	(36.0)	0.0
Gain on equity method investments	(74.6)	(5.8)	(0.1)
Pension settlement (gain) charges	0.0	35.2	0.0
Deferred income taxes	(131.1)	(39.6)	(5.6)
Amortization of deferred financing costs	7.7	6.2	3.8
Share-based compensation	17.9	20.3	18.8
Loss on divestiture	57.2	0.0	0.0
Trade receivables and receivables from long-term manufacturing contracts	(1.6)	(5.9)	(30.8)
Inventories, net	33.9	83.1	57.2
Prepaid expenses and other current assets	(17.3)	(17.8)	19.5
Trade accounts payable	(25.3)	(17.8)	(14.7)
Liabilities from long-term manufacturing contracts and advances, accrued compensation, and other current liabilities	(83.0)	(70.9)	(95.8)
Income taxes payable	6.1	(6.6)	29.4
Accrued pension and postretirement	(3.3)	20.3	(9.4)
Other, net	(4.5)	7.8	(5.0)
Net cash provided by operating activities from continuing operations	56.2	191.3	207.0
Investing activities from continuing operations
Capital expenditures	(38.3)	(54.2)	(69.3)
Proceeds from sales of property, plant, and equipment	2.1	56.3	0.8
Acquisitions of businesses, net of cash acquired	0.0	(0.9)	(1,350.9)
Proceeds from sale of equity method investment	114.7	0.0	0.0
Proceeds from divestiture, net of cash divested	83.9	0.0	696.7
Cross-currency swap settlement	9.1	0.0	0.0
Proceeds from Sale and Collection of Receivables	20.8	25.6	0.0
Other, net	0.4	0.0	0.4
Net cash provided by (used in) investing activities from continuing operations	192.7	26.8	(722.3)
Financing activities from continuing operations
Proceeds from long-term debt, net of discount	468.5	500.0	401.4
Repayments of long-term debt	(579.0)	(420.1)	(107.5)
Proceeds from revolving credit facilities	388.5	895.8	1,467.4
Repayments on revolving credit facilities	(475.4)	(1,124.2)	(1,009.4)
Payment of deferred financing costs	(7.4)	(7.4)	(3.3)
Payment of dividends on common stock	(63.4)	(62.5)	(61.3)
Proceeds from stock option exercises and other	1.0	2.4	21.0
Payments for employee taxes on net settlement equity awards	(3.4)	(7.0)	(12.7)
Other, net	(8.8)	(4.1)	(2.2)
Net cash (used in) provided by financing activities from continuing operations	(279.4)	(227.1)	693.4
Cash (used in) provided by continuing operations	(30.5)	(9.0)	178.1
Cash Provided by (Used in) Discontinued Operation [Abstract]
Cash Provided by (Used in) Operating Activity, Discontinued Operation	0.0	(23.3)	(136.8)
Cash Provided by (Used in) Investing Activity, Discontinued Operation	0.0	0.0	(7.6)
Total cash used in discontinued operations	0.0	(23.3)	(144.4)
Effect of exchange rates on cash and cash equivalents	(6.0)	10.0	(21.1)
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation, Total	(36.5)	(22.3)	12.6
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
At Beginning of Period	227.9	250.2	237.6
At End of Period	191.4	227.9	250.2
Cash paid for interest	89.5	123.4	80.6
Cash paid for income taxes	$ 67.9	$ 115.8	$ 238.6