Retirement benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
Components of net periodic benefit costs [Abstract]
Total net periodic pension costs (income)	$ (33)	$ (10)	$ (103)	$ (34)
Employer cash contributions to defined benefit pension plans			26
Expected employer cash contributions to defined benefit plan in current fiscal year	8		8
Selling, general and administrative expenses
Components of net periodic benefit costs [Abstract]
Service costs	1	2	4	4
Other income
Components of net periodic benefit costs [Abstract]
Interest costs	35	49	107	148
Expected returns on plan assets/other	(69)	(61)	(214)	(186)
UNITED STATES
Components of net periodic benefit costs [Abstract]
Profit sharing provision expense	57	58	171	183
Foreign Plan
Components of net periodic benefit costs [Abstract]
Cost recognized in the consolidated condensed statements of earnings	$ 31	$ 32	$ 98	$ 96