Revenue Recognition - Dual Reporting - Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2019	Oct. 01, 2018	Sep. 30, 2018
Current assets:
Receivables	$ 1,244.4	$ 1,194.6	$ 1,190.1
Other current assets	164.8	167.0	149.3
Deferred income taxes	200.0	180.8	179.6
Other assets	113.6	107.6	96.2
Current liabilities:
Contract liabilities	308.9	268.6	249.9
Customer returns, rebates and incentives	192.5	211.0	206.6
Other current liabilities	213.7	232.2	226.6
Shareowners’ equity:
Retained earnings	6,398.0	6,204.2	6,198.1
Accumulated other comprehensive loss	(940.3)		(941.9)
Impact of Adoption | Accounting Standards Update 2014-09
Current assets:
Receivables	(0.8)	4.5
Other current assets	(15.2)	17.7
Deferred income taxes	(3.0)	1.2
Other assets	(10.5)	11.4
Current liabilities:
Contract liabilities	(10.9)	18.7
Customer returns, rebates and incentives	(2.2)	4.4
Other current liabilities	(8.0)	5.6
Shareowners’ equity:
Retained earnings	(8.6)	$ 6.1
Accumulated other comprehensive loss	0.2
Balances without adoption of ASC 606
Current assets:
Receivables	1,243.6		1,190.1
Other current assets	149.6		149.3
Deferred income taxes	197.0		179.6
Other assets	103.1		96.2
Current liabilities:
Contract liabilities	298.0		249.9
Customer returns, rebates and incentives	190.3		206.6
Other current liabilities	205.7		226.6
Shareowners’ equity:
Retained earnings	6,389.4		$ 6,198.1
Accumulated other comprehensive loss	$ (940.1)