Basis of Presentation and Accounting Policies - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Reconciled Basic and Diluted EPS
Net income attributable to Rockwell Automation, Inc.	$ 1,387.4	$ 932.2	$ 1,358.1
Less: Allocation to participating securities	(5.9)	(2.9)	(2.1)
Net income available to common shareowners	$ 1,381.5	$ 929.3	$ 1,356.0
Basic weighted average outstanding shares (in shares)	114.8	115.9	116.0
Effect of dilutive securities
Diluted weighted average outstanding shares (in shares)	115.6	116.7	117.1
Earnings per share:
Basic (in dollars per share)	$ 12.03	$ 8.02	$ 11.69
Diluted (in dollars per share)	$ 11.95	$ 7.97	$ 11.58
Stock options
Effect of dilutive securities
Stock options (in shares)	0.7	0.7	1.0
Performance shares
Effect of dilutive securities
Stock options (in shares)	0.1	0.1	0.1