Shareowners' Equity - Schedule of Reclassifications Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income (Note 15)	$ (123.0)	$ 62.0	$ (71.0)
Sales	8,342.0	8,264.0	9,058.0
Cost of sales	(4,326.0)	(4,413.0)	(4,635.0)
Income before income taxes	917.0	1,100.0	1,608.0
Income tax provision	(168.0)	(152.0)	(330.0)
Net income attributable to Rockwell Automation, Inc.	869.0	953.0	1,387.0
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income attributable to Rockwell Automation, Inc.	22.0	(10.0)	64.0
Amortization of net actuarial loss (gain) | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income (Note 15)	29.0	0.0	(2.0)
Settlement and curtailment charges | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income (Note 15)	1.0	0.0	123.0
Pension and other postretirement benefit plan adjustments, net of tax | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	30.0	0.0	121.0
Income tax provision	(7.0)	0.0	(31.0)
Net income attributable to Rockwell Automation, Inc.	23.0	0.0	90.0
Accumulated gain (loss), net, cash flow hedge, parent | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales	1.0	(2.0)	(6.0)
Cost of sales	(7.0)	(19.0)	(33.0)
Interest expense	4.0	4.0	4.0
Income before income taxes	(2.0)	(17.0)	(35.0)
Income tax provision	1.0	5.0	9.0
Net income attributable to Rockwell Automation, Inc.	(1.0)	(12.0)	(26.0)
Accumulated currency translation adjustments, net of tax | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income (Note 15)	$ 0.0	$ 2.0	$ 0.0