Capital Stock (Changes in Common Shares) (Details) - shares	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Changes in Common Shares [Roll Forward]
Balance, beginning of year (shares)	222,372,418	222,199,845	221,838,696
Issuance of treasury shares for stock option and award plans (shares)	215,838	172,573	361,149
Balance, end of year (shares)	222,588,256	222,372,418	222,199,845