Business Segment and Geographic Information (Schedule of Geographic Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	$ 12,100.6	$ 12,600.0	$ 12,698.6
Plant and equipment, net	23,370.9	17,472.1	14,160.5
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	4,914.0	5,234.2	5,230.2
Plant and equipment, net	9,159.3	7,431.0	6,022.0
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	1,951.5	1,988.1	1,989.8
Plant and equipment, net	3,845.7	3,744.7	3,886.0
SAUDI ARABIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Plant and equipment, net	5,080.2	1,818.1	595.7
Other foreign operations
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	5,235.1	5,377.7	5,478.6
Plant and equipment, net	$ 5,285.7	$ 4,478.3	$ 3,656.8