Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 19,224.8	$ 18,719.1
Less: accumulated depreciation, depletion and amortization	(8,987.4)	(8,149.0)
Property, plant and equipment, net	10,237.4	10,570.1
Land and Buildings [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	2,695.0	2,626.0
Machinery and Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	16,271.9	15,853.1
Forestlands and Mineral Rights [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	135.3	120.0
Transportation Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	26.4	26.1
Leasehold Improvements [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 96.2	$ 93.9