Retirement benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2023	May 31, 2022	May 31, 2023	May 31, 2022
Components of net periodic benefit costs [Abstract]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]			Other income, net
Interest costs	$ 64	$ 37	$ 186	$ 115
Expected returns on plan assets/other	(81)	(70)	(237)	(216)
Total net periodic pension income	(17)	(32)	(48)	(97)
Employer cash contributions to defined benefit pension plans			19
Expected employer cash contributions to defined benefit plan in current fiscal year	17		17
Impairment of intangible assets			431	0
Selling, general and administrative expense
Components of net periodic benefit costs [Abstract]
Service costs	1	1	3	4
U.S. Retail Pharmacy
Components of net periodic benefit costs [Abstract]
Profit sharing provision expense	59	58	184	181
Foreign Plan
Components of net periodic benefit costs [Abstract]
Cost recognized in the consolidated condensed statements of earnings	$ 21	$ 21	$ 62	$ 69