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, 2025	Sep. 30, 2024	Sep. 30, 2023
Reconciled Basic and Diluted EPS
Net income attributable to Rockwell Automation, Inc.	$ 869.0	$ 953.0	$ 1,387.0
Less: Allocation to participating securities	(2.0)	(5.0)	(6.0)
Net income available to common shareowners	$ 867.0	$ 948.0	$ 1,381.0
Basic weighted average outstanding shares (in shares)	112.7	114.0	114.8
Effect of dilutive securities
Diluted weighted average outstanding shares (in shares)	113.1	114.5	115.6
Earnings per share:
Basic (in dollars per share)	$ 7.69	$ 8.32	$ 12.03
Diluted (in dollars per share)	$ 7.67	$ 8.28	$ 11.95
Stock options
Effect of dilutive securities
Dilutive securities (in shares)	0.4	0.5	0.7
Performance shares
Effect of dilutive securities
Dilutive securities (in shares)	0.0	0.0	0.1