Stockholders' Equity - Additional Information (Details) - USD ($)		3 Months Ended		12 Months Ended
	Jul. 20, 2018	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Nov. 13, 2020
Class of Stock [Line Items]
Preferred stock, shares authorized				5,000,000	5,000,000
Common stock, shares authorized				500,000,000	500,000,000
Stock repurchased during period (in shares)				0	1,400,000
Stock repurchased during period, value					$ 115,000,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt	$ 1,000,000,000		$ 100,000,000
Accelerated Share Repurchase Initial Delivery Percent of Total	80.00%
Stock Repurchased and Retired During Period, Value					$ 114,994,000	$ 1,100,000,000
Rockwell Automation
Class of Stock [Line Items]
Sale of Stock, Consideration Received on Transaction		$ 1,000,000,000
Stock issued for equity investment		10,582,010,000
Price per share (in dollars per share)		$ 94.50				$ 94.50
Accelerated Share Repurchase Agreement
Class of Stock [Line Items]
Stock repurchased during period (in shares)	8,200,000		1,200,000		3,000,000.0	8,200,000
Accelerated Share Repurchase Agreement | Final settlement
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Value						$ 200,000,000
Subsequent Event
Class of Stock [Line Items]
Stock authorized to repurchase							$ 1,000,000,000
Maximum
Class of Stock [Line Items]
Common stock, shares authorized				500,000,000
Stock authorized to repurchase				$ 1,500,000,000
Series A Junior Participating Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized				500,000