Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 17,211.2	$ 14,419.9
Less: accumulated depreciation, depletion and amortization	(6,041.9)	(5,337.4)
Property, plant and equipment, net	11,169.3	9,082.5
Land and Buildings [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	2,439.6	2,078.9
Machinery and Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	14,487.8	12,064.0
Forestlands and Mineral Rights [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	152.9	158.0
Transportation Equipment [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	31.8	30.1
Leasehold Improvements [Member]
Property, plant and equipment at cost:
Property, plant and equipment, at cost	$ 99.1	$ 88.9