Capital stock (Details) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Aug. 31, 2024	Aug. 31, 2023	Aug. 31, 2022	Jun. 30, 2018
Equity, Class of Treasury Stock [Line Items]
Shares repurchased during period (in shares)	0	0
Stock repurchased during current fiscal year, value	$ 69	$ 150	$ 187
Shares of common stock reserved for future issuances (in shares)	45,000
June 2018 Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized maximum amount				$ 10,000
Stock repurchase program, remaining authorized amount to be purchased	$ 2,000