Retirement benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2022	Nov. 30, 2021
Components of net periodic benefit costs [Abstract]
Service costs	$ 1	$ 1
Interest costs	59	39
Expected returns on plan assets/other	(75)	(74)
Total net periodic pension income	(15)	(33)
Employer cash contributions to defined benefit pension plans	1
Expected employer cash contributions to defined benefit plan in current fiscal year	35
U.S. Retail Pharmacy
Components of net periodic benefit costs [Abstract]
Profit sharing provision expense	65	69
Foreign Plan
Components of net periodic benefit costs [Abstract]
Cost recognized in the consolidated condensed statements of earnings	$ 20	$ 25