Sales (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2021	Nov. 30, 2020
Disaggregation of Revenue [Line Items]
Sales	$ 33,901	$ 31,438
Reportable Segments | United States
Disaggregation of Revenue [Line Items]
Sales	28,032	27,163
Reportable Segments | United States | Pharmacy
Disaggregation of Revenue [Line Items]
Sales	21,105	20,869
Reportable Segments | United States | Retail
Disaggregation of Revenue [Line Items]
Sales	6,927	6,294
Reportable Segments | International
Disaggregation of Revenue [Line Items]
Sales	5,818	4,285
Reportable Segments | International | Pharmacy
Disaggregation of Revenue [Line Items]
Sales	1,017	895
Reportable Segments | International | Retail
Disaggregation of Revenue [Line Items]
Sales	1,796	1,522
Reportable Segments | International | Wholesale
Disaggregation of Revenue [Line Items]
Sales	3,005	1,868
Reportable Segments | Walgreens Health
Disaggregation of Revenue [Line Items]
Sales	51	0
Corporate and Other
Disaggregation of Revenue [Line Items]
Sales	$ 0	$ (10)