Supplementary Balance Sheet Information (Details) - USD ($)	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Inventories, net of reserves:
Finished products	$ 114,300,000		$ 120,500,000
Inventory, Work in Process, Gross	42,700,000		42,400,000
Inventory, Raw Materials, Net of Reserves	108,500,000		106,700,000
Total inventories, net of reserves	265,500,000		269,600,000
Accumulated amortization of software and other intangible assets	602,200,000		597,000,000.0
Equity Securities without Readily Determinable Fair Value, Amount				$ 26,600,000
Equity Method Investment, Aggregate Cost	3,100,000
Loss on Sale of Investments	(300,000)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	(1,700,000)
Investments	47,700,000		$ 51,100,000
Capital Expenditures Incurred but Not yet Paid	4,000,000.0	$ 300,000
Equity Method Investment, Realized Gain (Loss) on Disposal	2,800,000
Non-cash Investing Activities	6,800,000	300,000
Restricted Stock or Unit Expense	$ 27,100,000	$ 9,900,000