Leases - rental expense (Details) - USD ($) $ in Millions	12 Months Ended
Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Leases [Abstract]
Minimum rentals	$ 3,447	$ 3,259	$ 3,355
Contingent rentals	68	59	60
Less: sublease rental income	(67)	(55)	(49)
Total rental expense	$ 3,448	$ 3,263	$ 3,366

No definition available.

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- Definition

The increases or decreases in lease payments that result from changes occurring after the inception of the lease in the factors (other than the passage of time) on which lease payments are based, except that any escalation of minimum lease payments relating to increases in construction or acquisition cost of the leased property or for increases in some measure of cost or value during the construction or preconstruction period, are excluded from contingent rentals. Contingent rentals also may include amounts for which the triggering events have not yet occurred or the specified targets for which have not yet been achieved (such as sales based percentage rent), but which events are considered probable of occurring or which specified targets are considered probable of being achieved.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
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+ Details

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- Definition

This element represents the payments that the lessee is obligated to make or can be required to make in connection with a property under the terms of an agreement classified as an operating lease, excluding contingent rentals and a guarantee by the lessee of the lessor's debt and the lessee's obligation to pay (apart from the rental payments) executory costs such as insurance, maintenance, and taxes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
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- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

+ Details

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- Definition

The total amount of sublease rental income recognized during the period that reduces the entity's rent expense incurred under operating leases.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 55
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