Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Mar. 31, 2024	Sep. 30, 2023
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 22,046.7	$ 21,876.2
Less: accumulated depreciation, depletion and amortization	(10,806.0)	(10,813.0)
Property, plant and equipment, net	11,240.7	11,063.2
Land and Buildings [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	3,135.7	2,994.7
Machinery and Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	17,763.8	17,682.4
Forestlands [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	109.9	105.2
Transportation Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	27.3	27.3
Leasehold Improvements [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	98.7	98.8
Construction in Progress [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 911.3	$ 967.8