Stock compensation plans (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	$ 385	$ 391	$ 155
Unrecognized compensation cost related to non-vested awards	$ 388
Compensation cost not yet recognized period for recognition	3 years
2021 Omnibus Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	$ 58	133	$ 155
Walgreens health
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total stock-based compensation expense	$ 327	$ 269