Consolidated Statements of Operations - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales		$ 6,943.9	$ 7,105.2	$ 6,418.3
Cost of products sold		5,244.7	5,368.6	4,825.0
Gross profit		1,699.2	1,736.6	1,593.3
Operating expense:
Selling, general and administrative		1,273.0	1,311.0	1,187.2
Depreciation		70.1	70.7	60.3
Amortization		321.0	207.1	141.2
Total operating expense		1,664.1	1,588.8	1,388.7
Income (loss) from operations		35.1	147.8	204.6
Interest expense, financing costs, and other		128.1	158.6	136.5
Loss on debt extinguishment		14.7	0.0	1.2
Income (loss) before provision for income taxes		(107.7)	(10.8)	68.1
Provision for (benefit from) income taxes		(26.8)	(0.2)	(30.5)
Net income (loss)		(80.9)	(10.6)	98.6
Dividends on Preferred Stock		24.0	24.0	18.0
Net income (loss) attributable to common shareholders		$ (104.9)	$ (34.6)	$ 80.6
Weighted-average common stock outstanding:
Basic	[1]	68,800,000	68,400,000	68,000,000.0
Diluted	[1]	68,800,000	68,400,000	69,200,000
Net income (loss) per share:
Basic	[1]	$ (1.52)	$ (0.51)	$ 1.07
Diluted	[1]	$ (1.52)	$ (0.51)	$ 1.05

[1] See Note 5 for detailed calculations and further discussion.