Supplemental information - Depreciation and Amortization Expense (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Feb. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019
Supplemental Cash Flow Elements [Abstract]
Depreciation expense	$ 375	$ 360	$ 734	$ 717
Intangible asset and other amortization	117	139	235	273
Total depreciation and amortization expense	$ 492	$ 499	$ 969	$ 990

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. 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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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- References

No definition available.

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