Retirement benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2020	Nov. 30, 2019
Components of net periodic benefit costs [Abstract]
Total net periodic pension costs (income)	$ (45)	$ (34)
Employer cash contributions to defined benefit pension plans	10
Expected employer cash contributions to defined benefit plan in current fiscal year	29
Selling, general and administrative expenses
Components of net periodic benefit costs [Abstract]
Service costs	2	2
Other income
Components of net periodic benefit costs [Abstract]
Interest costs	33	35
Expected returns on plan assets/other	(80)	(71)
UNITED STATES
Components of net periodic benefit costs [Abstract]
Profit sharing provision expense	57	58
Foreign Plan
Components of net periodic benefit costs [Abstract]
Cost recognized in the consolidated condensed statements of earnings	$ 30	$ 38