Sales (Details) - USD ($) $ in Millions	3 Months Ended
Nov. 30, 2020	Nov. 30, 2019
Disaggregation of Revenue [Line Items]
Sales	$ 36,307	$ 34,339
Reportable Segments \| Retail Pharmacy USA
Disaggregation of Revenue [Line Items]
Sales	27,163	26,133
Reportable Segments \| Retail Pharmacy USA \| Pharmacy
Disaggregation of Revenue [Line Items]
Sales	20,869	19,705
Reportable Segments \| Retail Pharmacy USA \| Retail
Disaggregation of Revenue [Line Items]
Sales	6,294	6,428
Reportable Segments \| Retail Pharmacy International
Disaggregation of Revenue [Line Items]
Sales	2,574	2,745
Reportable Segments \| Retail Pharmacy International \| Pharmacy
Disaggregation of Revenue [Line Items]
Sales	1,002	1,001
Reportable Segments \| Retail Pharmacy International \| Retail
Disaggregation of Revenue [Line Items]
Sales	1,572	1,744
Reportable Segments \| Pharmaceutical Wholesale
Disaggregation of Revenue [Line Items]
Sales	7,125	6,007
Eliminations
Disaggregation of Revenue [Line Items]
Sales	$ (555)	$ (545)

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details