Earnings per share - Schedule of Reconciliation of Numerator and Denominator of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024
Numerator:
Net income	$ 845	$ 949	$ 1,653	$ 1,647
Denominator:
Basic - weighted average common shares (in shares)	126.2	128.8	126.4	128.7
Dilutive effect of equity-based awards (in shares)	1.9	2.0	1.9	2.0
Diluted - weighted-average common shares (in shares)	128.1	130.8	128.2	130.7
Basic earnings per share (in USD per share)	$ 6.69	$ 7.37	$ 13.08	$ 12.80
Diluted earnings per share (in USD per share)	$ 6.60	$ 7.25	$ 12.89	$ 12.60