Retirement benefits - changes in benefit obligations (Details) - Pension Plan - USD ($) $ in Millions	12 Months Ended
Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2018
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	$ 8,834	$ 8,293
Service costs	5	4	$ 5
Interest costs	143	196	193
Amendments/other	0	22
Net actuarial loss	495	1,212
Benefits paid	(333)	(363)
Currency translation adjustments	805	(530)
Benefit obligation at end of year	$ 9,949	$ 8,834	$ 8,293

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

+ References

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan.

+ References

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- Definition

Amount of cost recognized for passage of time related to defined benefit plan.

+ References

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Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan.

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Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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