Consolidated Statement of Shareowners' Equity - USD ($) $ in Millions	Total		Adoption of accounting standard	Total attributable to Rockwell Automation, Inc.	Total attributable to Rockwell Automation, Inc. Adoption of accounting standard	Common stock	Additional paid-in capital	Retained earnings		Retained earnings Adoption of accounting standard	Accumulated other comprehensive loss	Accumulated other comprehensive loss Adoption of accounting standard	Common stock in treasury, at cost	Noncontrolling interests
Beginning of period at Sep. 30, 2017	$ 2,663.6			$ 2,663.6		$ 181.4	$ 1,638.0	$ 6,103.4			$ (1,179.2)		$ (4,080.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	535.5			535.5				535.5
Other comprehensive income (loss)	237.3			237.3							237.3
Common stock issued (including share-based compensation impact)	122.4			122.4			43.4						79.0
Share Repurchases	(1,500.5)			(1,500.5)									(1,500.5)
Cash dividends declared	(440.8)	[1]		(440.8)				(440.8)	[1]
End of period at Sep. 30, 2018	1,617.5		$ 6.1	1,617.5	$ 6.1	181.4	1,681.4	6,198.1		$ 6.1	(941.9)		(5,501.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	695.8			695.8				695.8
Other comprehensive income (loss)	(546.1)			(546.1)							(546.1)
Common stock issued (including share-based compensation impact)	90.7			90.7			27.7						63.0
Share Repurchases	(1,000.0)			(1,000.0)									(1,000.0)
Cash dividends declared	(459.8)	[1]		(459.8)				(459.8)	[1]
End of period at Sep. 30, 2019	404.2		$ 2.2	404.2	$ 2.2	181.4	1,709.1	6,440.2		$ 149.0	(1,488.0)	$ (146.8)	(6,438.5)	$ 0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,023.2			1,023.4				1,023.4						(0.2)
Other comprehensive income (loss)	16.5			16.8							16.8			(0.3)
Common stock issued (including share-based compensation impact)	260.5			260.5			77.0						183.5
Share Repurchases	(254.9)			(254.9)									(254.9)
Cash dividends declared	(472.8)	[1]		(472.8)				(472.8)	[1]
Change in noncontrolling interest	367.9			48.4			44.6				3.8			319.5
End of period at Sep. 30, 2020	$ 1,346.8			$ 1,027.8		$ 181.4	$ 1,830.7	$ 7,139.8			$ (1,614.2)		$ (6,509.9)	$ 319.0

[1] Cash dividends were $4.08 per share in 2020; $3.88 per share in 2019; and $3.51 per share in 2018.