Stockholders' Equity (Details) - USD ($)				12 Months Ended
	Jul. 20, 2018	Jul. 19, 2018	May 03, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	May 03, 2019
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 authorized to repurchase				$ 1,500,000,000
Stock repurchased during period (in shares)				1,400,000		900,000
Repurchases of common stock				$ 114,994,000	$ 1,100,000,000	$ 50,991,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt	$ 1,000,000,000						$ 100,000,000
Accelerated Share Repurchase Initial Delivery Percent of Total	80.00%
Series A Junior Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized				500,000
Rockwell Automation [Member]
Class of Stock [Line Items]
Sale of Stock, Consideration Received on Transaction		$ 1,000,000,000
Stock issued for equity investment		10,582,010
Price per share (in dollars per share)		$ 94.50
Accelerated Share Repurchase Agreement [Member]
Class of Stock [Line Items]
Stock repurchased during period (in shares)	8,200,000		1,200,000	3,000,000.0
Accelerated Share Repurchase Agreement [Member] | Final settlement [Member]
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Value				$ 200,000,000