Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 22,295.5	$ 21,876.2
Less: accumulated depreciation, depletion and amortization	(11,065.3)	(10,813.0)
Property, plant and equipment, net	11,230.2	11,063.2
Land and Buildings [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	3,099.3	2,994.7
Machinery and Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	18,026.7	17,682.4
Forestlands [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	113.3	105.2
Transportation Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	27.9	27.3
Leasehold Improvements [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	100.9	98.8
Construction in Progress [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 927.4	$ 967.8