Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 17,915.5	$ 17,461.3
Less: accumulated depreciation, depletion and amortization	(7,136.6)	(6,271.8)
Property, plant and equipment, net	10,778.9	11,189.5
Land and Buildings [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	2,524.7	2,442.3
Machinery and Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	15,147.3	14,743.6
Forestlands and Mineral Rights [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	110.8	144.0
Transportation Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	29.1	31.2
Leasehold Improvements [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 103.6	$ 100.2