Retirement benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2019	Nov. 30, 2018
Components of net periodic benefit costs [Abstract]
Total net periodic pension costs (income)	$ (34)	$ (10)
Employer cash contributions to defined benefit pension plans	8
Expected employer cash contributions to defined benefit plan in current fiscal year	22
Selling, general and administrative (expenses) income
Components of net periodic benefit costs [Abstract]
Service costs	2	1
Other income (expense)
Components of net periodic benefit costs [Abstract]
Interest costs	35	49
Expected returns on plan assets/other	(71)	(60)
UNITED STATES
Components of net periodic benefit costs [Abstract]
Profit sharing provision expense	58	61
Foreign Plan
Components of net periodic benefit costs [Abstract]
Cost recognized in the consolidated condensed statements of earnings	$ 38	$ 31