Shareowners' Equity - Schedule of Reclassifications Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income	$ 1.6	$ (5.7)	$ 29.7
Sales	7,760.4	6,997.4	6,329.8
Cost of sales	(4,658.4)	(4,099.7)	(3,734.6)
Selling, general and administrative expenses	(1,766.7)	(1,680.0)	(1,479.8)
Interest expense	(123.2)	(94.6)	(103.5)
Income before income taxes	1,073.6	1,526.2	1,136.1
Income tax provision	(154.5)	(181.9)	(112.9)
Net income attributable to Rockwell Automation, Inc.	932.2	1,358.1	1,023.4
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income attributable to Rockwell Automation, Inc.	62.6	156.0	98.3
Amortization of prior service credit | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income	(0.2)	(4.0)	(4.5)
Amortization of net actuarial loss | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income	60.1	142.5	148.7
Settlement and curtailment charges | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income	38.6	39.8	0.0
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	98.5	178.3	144.2
Income tax provision	(22.9)	(40.1)	(34.7)
Net income attributable to Rockwell Automation, Inc.	75.6	138.2	109.5
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	(0.7)	(1.9)	0.7
Cost of sales	(21.8)	25.4	(19.6)
Selling, general and administrative expenses	0.9	(1.5)	1.4
Interest expense	3.6	2.3	2.1
Income before income taxes	(18.0)	24.3	(15.4)
Income tax provision	5.0	(6.5)	4.2
Net income attributable to Rockwell Automation, Inc.	$ (13.0)	$ 17.8	$ (11.2)