Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 23,822	$ 21,136	$ 24,152
Total other comprehensive (loss) income	(728)	1,669	148
Ending balance	29,366	23,822	21,136
Accumulated other comprehensive income (loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(2,109)	(3,771)	(3,897)
Other comprehensive (loss) income before reclassification adjustments	(97)	1,022	(69)
Amounts reclassified from AOCI	(565)	6	0
Business disposal	(6)	792
Tax benefit (provision)	(27)	(157)	195
Total other comprehensive (loss) income	(696)	1,663	126
Ending balance	(2,805)	(2,109)	(3,771)
Pension/post-retirement obligations
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(359)	(748)	(48)
Other comprehensive (loss) income before reclassification adjustments	278	532	(861)
Amounts reclassified from AOCI	(22)	(8)	(8)
Business disposal	(6)	(4)
Tax benefit (provision)	(48)	(132)	169
Total other comprehensive (loss) income	203	389	(700)
Ending balance	(157)	(359)	(748)
Unrealized gain (loss) on cash flow hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(10)	(31)	(24)
Other comprehensive (loss) income before reclassification adjustments	6	10	(12)
Amounts reclassified from AOCI	3	17	5
Business disposal	0	0
Tax benefit (provision)	(2)	(6)	1
Total other comprehensive (loss) income	7	21	(6)
Ending balance	(3)	(10)	(31)
Net investment hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(35)	(34)	55
Other comprehensive (loss) income before reclassification adjustments	327	(6)	(113)
Amounts reclassified from AOCI	0	0	0
Business disposal	0	0
Tax benefit (provision)	(79)	6	23
Total other comprehensive (loss) income	248	(1)	(90)
Ending balance	213	(35)	(34)
Unrealized gain (loss) on available for sale debt securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	96	0	0
Other comprehensive (loss) income before reclassification adjustments	451	127	0
Amounts reclassified from AOCI	(577)	0	0
Business disposal	0	0
Tax benefit (provision)	32	(31)	0
Total other comprehensive (loss) income	(95)	96	0
Ending balance	1	96	0
Share of AOCI of equity method investments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(29)	(10)	3
Other comprehensive (loss) income before reclassification adjustments	(326)	(24)	(16)
Amounts reclassified from AOCI	31	0	0
Business disposal	0	0
Tax benefit (provision)	70	6	3
Total other comprehensive (loss) income	(226)	(18)	(13)
Ending balance	(254)	(29)	(10)
Cumulative translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,772)	(2,948)	(3,884)
Other comprehensive (loss) income before reclassification adjustments	(833)	384	934
Amounts reclassified from AOCI	0	(3)	3
Business disposal	0	795
Tax benefit (provision)	0	0	(1)
Total other comprehensive (loss) income	(833)	1,176	936
Ending balance	$ (2,605)	$ (1,772)	$ (2,948)