Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2021	May 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 21,625	$ 24,334	$ 21,136	$ 24,152
Total other comprehensive income	131	(474)	607	31
Ending balance	22,596	21,323	22,596	21,323
Pension/ post-retirement obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(739)	(57)	(748)	(48)
Other comprehensive income (loss) before reclassification adjustments	0	(4)	16	(12)
Amounts reclassified from AOCI	(2)	(3)	(6)	(3)
Tax benefit (provision)	0	4	(3)	4
Total other comprehensive income	(1)	(2)	8	(11)
Ending balance	(740)	(59)	(740)	(59)
Unrealized gain (loss) on cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(18)	(24)	(31)	(24)
Other comprehensive income (loss) before reclassification adjustments	(3)	(8)	11	(9)
Amounts reclassified from AOCI	14	1	16	4
Tax benefit (provision)	(3)	2	(7)	1
Total other comprehensive income	8	(5)	21	(4)
Ending balance	(10)	(29)	(10)	(29)
Net investment hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(90)	34	(34)	55
Other comprehensive income (loss) before reclassification adjustments	(30)	59	(110)	31
Amounts reclassified from AOCI	0	0	0	0
Tax benefit (provision)	7	(13)	31	(6)
Total other comprehensive income	(23)	46	(79)	25
Ending balance	(113)	80	(113)	80
Unrealized gain (loss) on available for sale securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	0		0
Other comprehensive income (loss) before reclassification adjustments	5		5
Amounts reclassified from AOCI	0		0
Tax benefit (provision)	0		0
Total other comprehensive income	5		5
Ending balance	5		5
Share of OCI of equity method investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	10	(1)	(10)	3
Other comprehensive income (loss) before reclassification adjustments	2	(18)	21	(23)
Amounts reclassified from AOCI	0	0	0	0
Tax benefit (provision)	(6)	3	(5)	3
Total other comprehensive income	(4)	(15)	16	(20)
Ending balance	6	(16)	6	(16)
Cumulative translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,469)	(3,360)	(2,948)	(3,884)
Other comprehensive income (loss) before reclassification adjustments	141	(482)	615	39
Amounts reclassified from AOCI	1	0	6	0
Tax benefit (provision)	0	(5)	0	(2)
Total other comprehensive income	142	(487)	621	37
Ending balance	(2,327)	(3,847)	(2,327)	(3,847)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,306)	(3,407)	(3,771)	(3,897)
Other comprehensive income (loss) before reclassification adjustments	115	(453)	558	26
Amounts reclassified from AOCI	13	(1)	17	1
Tax benefit (provision)	(1)	(9)	17	0
Total other comprehensive income	127	(463)	591	27
Ending balance	$ (3,180)	$ (3,871)	$ (3,180)	$ (3,871)