Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Assets, Current [Abstract]
Cash and cash equivalents	$ 420.7	$ 409.1
Receivables, net	83.5	81.3
Inventories, net	31.5	33.3
Prepaid expenses and other current assets	55.2	65.5
Short-term investments	119.7	347.5
Total current assets	710.6	936.7
Noncurrent assets
Property, plant and equipment, net	841.5	818.3
Operating lease assets	273.1	266.5
Goodwill and intangibles, net	685.6	680.6
Other noncurrent assets	198.5	187.8
Total noncurrent assets	1,998.7	1,953.2
Total assets	2,709.3	2,889.9
Current liabilities
Current portion of long-term debt	23.8	23.8
Trade and other payables	77.2	118.7
Accrued expenses and other liabilities	216.4	215.9
Current liabilities held for sale	0.0	3.9
Total current liabilities	317.4	362.3
Noncurrent liabilities
Long-term debt	1,556.8	1,562.3
Employee benefit obligations	169.9	168.0
Operating lease liabilities	253.9	247.3
Other noncurrent liabilities	346.5	346.8
Total noncurrent liabilities	2,327.1	2,324.4
Commitments and contingencies
Stockholders’ equity
Preferred stock, no par value, 40 shares authorized; no shares issued and outstanding	0.0	0.0
Common stock, par value $0.01 per share, 400.0 shares authorized; 129.6 and 134.8 shares issued and outstanding at December 31, 2023 and September 30, 2023, respectively	1.3	1.3
Paid-in capital	46.3	48.0
Retained (deficit) earnings	(0.2)	140.7
Accumulated other comprehensive income	17.4	13.2
Total stockholders’ equity	64.8	203.2
Total liabilities and stockholders’ equity	$ 2,709.3	$ 2,889.9