Business Segment and Geographic Information (Schedule of Geographic Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	$ 12,600.0	$ 12,698.6	$ 10,323.0
Plant and equipment, net	17,472.1	14,160.5	13,254.6
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	5,234.2	5,230.2	3,895.8
Plant and equipment, net	7,431.0	6,022.0	5,187.8
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	1,988.1	1,989.8	1,828.0
Plant and equipment, net	3,744.7	3,886.0	4,137.7
SAUDI ARABIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Plant and equipment, net	1,818.1	595.7	29.0
Other foreign operations
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales	5,377.7	5,478.6	4,599.2
Plant and equipment, net	$ 4,478.3	$ 3,656.8	$ 3,900.1