Retirement benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021
Components of net periodic benefit costs [Abstract]
Total net periodic pension income	$ (33)	$ (47)	$ (65)	$ (92)
Employer cash contributions to defined benefit pension plans			3
Expected employer cash contributions to defined benefit plan in current fiscal year	38		38
Selling, general and administrative expenses
Components of net periodic benefit costs [Abstract]
Service costs	1	2	3	3
Other income (expense)
Components of net periodic benefit costs [Abstract]
Interest costs	38	35	78	68
Expected returns on plan assets/other	(72)	(83)	(146)	(163)
United States
Components of net periodic benefit costs [Abstract]
Profit sharing provision expense	54	55	123	112
Foreign Plan
Components of net periodic benefit costs [Abstract]
Cost recognized in the consolidated condensed statements of earnings	$ 23	$ 26	$ 48	$ 52