Income taxes - provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Current provision
Federal	$ 201	$ 866	$ 759
State	46	103	45
Non–U.S.	241	353	390
Total current provisions for income taxes	488	1,322	1,194
Deferred provision
Federal – tax law change	0	(648)	0
Federal – excluding tax law change	151	304	(306)
State	4	78	(24)
Non–U.S. – tax law change	0	0	(80)
Non–U.S. – excluding tax law change	(55)	(58)	(24)
Total non-current provisions for income taxes	100	(324)	(434)
Income tax provision	$ 588	$ 998	$ 760