Summarized Financial Information of Equity Affiliates (Table of Summarized Financial Information of Equity Affiliates) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Schedule of Equity Method Investments [Line Items]
Current assets	$ 8,684.9				$ 4,618.3				$ 8,684.9	$ 4,618.3
Noncurrent assets	16,483.6				14,324.5				16,483.6	14,324.5
Current liabilities	2,416.7				1,820.9				2,416.7	1,820.9
Noncurrent liabilities	10,308.7				5,733.6				10,308.7	5,733.6
Net sales	2,320.1	$ 2,065.2	$ 2,216.3	$ 2,254.7	2,283.2	$ 2,224.0	$ 2,187.7	$ 2,224.0	8,856.3	8,918.9	$ 8,930.2
Sales less cost of sales	753.6	720.3	756.2	768.1	792.4	758.0	713.0	651.0	2,998.2	2,914.4
Operating income	494.7	457.1	504.7	488.9	518.7	500.2	433.5	357.0	1,945.4	1,809.4	1,490.7
Net income	494.7	$ 457.1	$ 490.4	$ 488.9	518.7	$ 500.2	$ 433.5	$ 357.0	1,931.1	1,809.4	1,532.9
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Current assets	1,943.5				1,660.6				1,943.5	1,660.6
Noncurrent assets	4,529.2				4,400.4				4,529.2	4,400.4
Current liabilities	765.3				725.1				765.3	725.1
Noncurrent liabilities	$ 2,958.8				$ 2,853.6				2,958.8	2,853.6
Net sales									2,809.1	2,885.6	2,663.1
Sales less cost of sales									1,212.5	1,193.4	1,050.6
Operating income									748.6	763.4	635.3
Net income									$ 567.8	$ 492.4	$ 388.0