CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales		$ 6,856.8	$ 8,382.0	$ 7,705.5
Cost of sales		5,736.5	6,864.6	6,346.9
Gross income		1,120.3	1,517.4	1,358.6
Operating expenses:
Selling, general and administrative		620.6	683.5	664.3
Amortization of purchased intangibles		11.0	36.9	38.3
Total operating expenses		631.6	720.4	702.6
Operating income		488.7	797.0	656.0
Other income (expense):
Interest expense		(59.3)	(54.4)	(70.9)
Interest income		7.5	6.8	15.3
Miscellaneous, net	[1]	2.2	1.3	(5.8)
Income before income taxes and earnings (losses) of unconsolidated affiliates		439.1	750.7	594.6
Provision for income taxes		112.8	171.3	123.8
Income before earnings (losses) of unconsolidated affiliates		326.3	579.4	470.8
Equity in earnings (losses) of unconsolidated affiliates		(1.8)		1.1
Net income		$ 324.5	$ 579.4	$ 471.9
Earnings per share:
Basic		$ 4.76	$ 8.30	$ 6.38
Diluted		$ 4.72	$ 8.21	$ 6.29

[1] Fiscal 2020 results include a $6.2 million gain from insurance proceeds in excess of property loss in the Commercial segment.