Income taxes - provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Current provision
Federal	$ 866	$ 759	$ 999
State	103	45	56
Non–U.S.	353	390	371
Total current provisions for income taxes	1,322	1,194	1,426
Deferred provision
Federal – tax law change	(648)	0	0
Federal – excluding tax law change	304	(306)	(183)
State	78	(24)	6
Non–U.S. – tax law change	0	(80)	(182)
Non–U.S. – excluding tax law change	(58)	(24)	(70)
Total non-current provisions for income taxes	(324)	(434)	(429)
Income tax provision	$ 998	$ 760	$ 997