Shareholders’ equity - Narrative (Details) $ in Billions	3 Months Ended			6 Months Ended
	Jan. 31, 2025 USD ($) shares	Oct. 31, 2024 shares	Jan. 31, 2024 shares	Jan. 31, 2025 USD ($) trust shares	Jan. 31, 2024 shares	Mar. 31, 2025 USD ($)
Class of Stock [Line Items]
Number of employee benefit trusts | trust				2
Stock repurchased | $	$ 3.6			$ 3.6
Subsequent Event
Class of Stock [Line Items]
Authorized stock to repurchased | $						$ 1.0
Remaining stock authorized for repurchase | $						$ 5.0
Common Stock
Class of Stock [Line Items]
Change in shares issued (in shares) | shares	0	201,343,253	0	201,343,253	0
Ordinary shares
Class of Stock [Line Items]
Treasury stock, shares, retired | shares		30,827,929
Ordinary shares canceled (in shares) | shares		201,343,253