Equity Affiliates (Table of Summarized Financial Information of Equity Affiliates) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Schedule of Equity Method Investments [Line Items]
Total current assets	$ 6,363.0	$ 5,200.5
Total noncurrent assets	33,211.6	26,802.0
Total current liabilities	4,179.6	3,895.8
Total noncurrent liabilities	16,721.3	12,446.4
Sales and other income	12,100.6	12,600.0	$ 12,698.6
Operating income	4,466.1	2,494.6	2,338.8
Net income	3,862.4	2,338.6	2,266.5
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total current assets	3,197.2	3,097.1
Total noncurrent assets	14,719.8	14,468.2
Total current liabilities	1,138.3	1,145.7
Total noncurrent liabilities	11,690.4	11,934.0
Sales and other income	5,666.4	5,192.9	4,124.4
Financing revenue	1,128.6	1,011.3	674.6
Gross profit	2,722.0	2,465.5	1,894.0
Operating income	2,149.3	1,847.4	1,320.1
Net income	$ 1,209.5	$ 1,062.9	$ 895.1