Description of Business and Summary of Significant Accounting Policies (Reclassification from AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2019
Realized losses (gains) on derivative instruments:
Foreign exchange contracts	$ 26,926	$ 25,335	$ 23,369
Interest rate contracts	130	174	188
Actuarial (gain) loss	(10)	(3)	1
Prior service cost	1	0	0
(Gain) loss on securities	2	(49)	(30)
Total amounts reclassified from AOCI	(944)	(261)	(451)
Reclassification out of AOCI
Realized losses (gains) on derivative instruments:
Total amounts reclassified from AOCI	(56)	47	54
Reclassification out of AOCI | Realized losses (gains) on derivative instruments
Realized losses (gains) on derivative instruments:
Loss to be reclassified in next 12 months	6
Reclassification out of AOCI | Realized losses (gains) on derivative instruments | Foreign exchange contracts
Realized losses (gains) on derivative instruments:
Foreign exchange contracts	(44)	15	22
Reclassification out of AOCI | Realized losses (gains) on derivative instruments | Interest rate contracts
Realized losses (gains) on derivative instruments:
Interest rate contracts	3	(1)	(2)
Reclassification out of AOCI | Actuarial (gain) loss
Realized losses (gains) on derivative instruments:
Actuarial (gain) loss	(16)	(3)	1
Reclassification out of AOCI | Available for sale securities
Realized losses (gains) on derivative instruments:
(Gain) loss on securities	0	36	33
Reclassification out of AOCI | Prior service cost
Realized losses (gains) on derivative instruments:
Prior service cost	$ 1	$ 0	$ 0