Segment reporting (Details) $ in Millions	3 Months Ended	6 Months Ended
Feb. 29, 2020 USD ($)	Feb. 28, 2019 USD ($)	Feb. 29, 2020 USD ($) segment	Feb. 28, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| segment			3
Sales	$ 35,820	$ 34,528	$ 70,160	$ 68,321
Adjusted operating income	1,703	1,935	3,166	3,667
Acquisition-related amortization and impairment	(117)	(123)	(235)	(246)
Acquisition-related costs	(99)	(82)	(223)	(148)
Transformational cost management	(123)	(150)	(209)	(179)
Adjustments to equity earnings in AmerisourceBergen	(73)	(9)	(152)	(54)
LIFO provision	(28)	(8)	(61)	(48)
Store optimization	(30)	(31)	(39)	(51)
Certain legal and regulatory accruals and settlements	0	(14)	0	(24)
Operating income	1,233	1,517	2,247	2,918
Reportable Segments \| Retail Pharmacy USA
Segment Reporting Information [Line Items]
Sales	27,245	26,257	53,377	51,979
Adjusted operating income	1,267	1,455	2,423	2,834
Reportable Segments \| Retail Pharmacy International
Segment Reporting Information [Line Items]
Sales	3,056	3,082	5,801	5,982
Adjusted operating income	198	256	276	388
Reportable Segments \| Pharmaceutical Wholesale
Segment Reporting Information [Line Items]
Sales	6,066	5,738	12,072	11,446
Adjusted operating income	235	225	464	445
Eliminations
Segment Reporting Information [Line Items]
Sales	(546)	(549)	(1,091)	(1,086)
Adjusted operating income	$ 2	$ (1)	$ 2	$ 0

The amount of expense recognized in the current period that reflects the allocation of capitalized costs associated with acquisition of business. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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