Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended				6 Months Ended
	Dec. 15, 2025	Oct. 31, 2025	Oct. 30, 2024	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2025	Dec. 31, 2024
Class of Stock [Line Items]
Purchase of treasury shares								$ 758	$ 390
Retirement of treasury stock						0			0
$375 million share repurchase program
Class of Stock [Line Items]
Purchase of treasury shares				$ 375	$ 375		$ 375
Share Repurchase Programs
Class of Stock [Line Items]
Share Repurchase Program, Excise Tax								8	$ 15
Share Repurchase Program, Excise Tax								8	15
Treasury Stock, Common
Class of Stock [Line Items]
Purchase of treasury shares								$ 750	$ 375
Treasury Stock, Shares, Acquired				(2,000,000)		0		(4,000,000)	(3,000,000)
Retirement of treasury stock				56,000,000		56,000,000			56,000,000
Treasury Stock, Common | $375 million share repurchase program
Class of Stock [Line Items]
Treasury shares acquired, average price per share (in usd per share)	$ 200.00	$ 151.88	$ 110.10	$ 190.22	$ 148.12		$ 109.65
Treasury Stock, Common | $375 million share repurchase program
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired	(300,000)	(400,000)	(700,000)	(1,600,000)	(2,000,000.0)		(2,700,000)