Shareowners' Equity - Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Equity, Class of Treasury Stock [Line Items]
Common stock, authorized (in shares)	1,000,000,000
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, authorized (in shares)	25,000,000
Common stock reserved for various incentive plans (in shares)	10,600,000
Outstanding purchase of common stock recorded in accounts payable	$ 1.0
Changes in outstanding common shares
Beginning balance (in shares)	113,100,000	114,800,000	115,200,000
Treasury stock purchases (in shares)	(1,500,000)	(2,200,000)	(1,200,000)
Common stock issued (including share based compensation impact) (in shares)	800,000	500,000	800,000
Ending balance (in shares)	112,400,000	113,100,000	114,800,000
Common stock in treasury, at cost
Equity, Class of Treasury Stock [Line Items]
Treasury stock retired (in shares)	40,000,000