Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 238.9	$ 590.4
Other comprehensive income (loss):
Pension and other postretirement benefit plan adjustments (net of tax (expense) of ($5.4) and ($8.2))	16.9	27.6
Currency translation adjustments	(19.5)	69.2
Net change in cash flow hedges (net of tax (expense) benefit of ($2.6) and $3.7)	7.5	(9.8)
Other comprehensive income	4.9	87.0
Comprehensive income	243.8	677.4
Comprehensive loss attributable to noncontrolling interests	(2.6)	(2.8)
Comprehensive income attributable to Rockwell Automation, Inc.	$ 246.4	$ 680.2