Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 24,334	$ 25,413	$ 24,152	$ 26,689
Total other comprehensive income (loss)	(474)	(702)	31	(399)
Ending Balance	21,323	24,771	21,323	24,771
Pension/ post-retirement obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(57)	95	(48)	101
Other comprehensive income (loss) before reclassification adjustments	(4)	1	(12)	1
Amounts reclassified from AOCI	(3)	(4)	(3)	(12)
Tax benefit (provision)	4	1	4	3
Total other comprehensive income (loss)	(2)	(2)	(11)	(8)
Ending Balance	(59)	93	(59)	93
Unrealized gain (loss) on cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(24)	(28)	(24)	(30)
Other comprehensive income (loss) before reclassification adjustments	(8)	2	(9)	1
Amounts reclassified from AOCI	1	1	4	4
Tax benefit (provision)	2	(1)	1	0
Total other comprehensive income (loss)	(5)	3	(4)	4
Ending Balance	(29)	(25)	(29)	(25)
Net investment hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	34	(12)	55	0
Other comprehensive income (loss) before reclassification adjustments	59	54	31	39
Amounts reclassified from AOCI		0	0	0
Tax benefit (provision)	(13)	(13)	(6)	(10)
Total other comprehensive income (loss)	46	41	25	29
Ending Balance	80	29	80	29
Share of OCI of equity method investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(1)	2	3	3
Other comprehensive income (loss) before reclassification adjustments	(18)	1	(23)	(1)
Amounts reclassified from AOCI	0	0	0	0
Tax benefit (provision)	3	0	3	0
Total other comprehensive income (loss)	(15)	1	(20)	(1)
Ending Balance	(16)	4	(16)	4
Cumulative translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,360)	(2,762)	(3,884)	(3,076)
Other comprehensive income (loss) before reclassification adjustments	(482)	(733)	39	(415)
Amounts reclassified from AOCI	0	0	0	0
Tax benefit (provision)	(5)	1	(2)	(1)
Total other comprehensive income (loss)	(487)	(732)	37	(416)
Ending Balance	(3,847)	(3,493)	(3,847)	(3,493)
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,407)	(2,705)	(3,897)	(3,002)
Other comprehensive income (loss) before reclassification adjustments	(453)	(675)	26	(376)
Amounts reclassified from AOCI	(1)	(2)	1	(8)
Tax benefit (provision)	(9)	(12)	0	(8)
Total other comprehensive income (loss)	(463)	(689)	27	(393)
Ending Balance	$ (3,871)	$ (3,393)	$ (3,871)	$ (3,393)