Retirement benefits - accumulated benefit obligations in excess of plan assets (Details) - Pension Plan - USD ($) $ in Millions	Aug. 31, 2019	Aug. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 8,834	$ 8,293
Accumulated benefit obligation	8,823	8,285
Fair value of plan assets	$ 9,131	$ 8,676

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

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-Publisher FASB
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Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

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Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

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