Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2020	Nov. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 21,136	$ 24,152
Total other comprehensive income	94	600
Ending Balance	20,563	24,314
Pension/ post-retirement obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(748)	(48)
Other comprehensive income (loss) before reclassification adjustments	17	(12)
Amounts reclassified from AOCI	(2)	2
Tax benefit (provision)	(4)	2
Total other comprehensive income	11	(7)
Ending Balance	(736)	(55)
Unrealized gain (loss) on cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(31)	(24)
Other comprehensive income (loss) before reclassification adjustments	4	(1)
Amounts reclassified from AOCI	1	1
Tax benefit (provision)	(1)	0
Total other comprehensive income	4	0
Ending Balance	(27)	(24)
Net investment hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(34)	55
Other comprehensive income (loss) before reclassification adjustments	(14)	(55)
Amounts reclassified from AOCI	0	0
Tax benefit (provision)	8	13
Total other comprehensive income	(7)	(42)
Ending Balance	(41)	14
Share of OCI of equity method investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(10)	3
Other comprehensive income (loss) before reclassification adjustments	7	(10)
Amounts reclassified from AOCI	0	0
Tax benefit (provision)	(1)	2
Total other comprehensive income	5	(8)
Ending Balance	(5)	5
Cumulative translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(2,948)	(3,884)
Other comprehensive income (loss) before reclassification adjustments	72	642
Amounts reclassified from AOCI	3	0
Tax benefit (provision)	0	0
Total other comprehensive income	75	642
Ending Balance	(2,873)	(3,242)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,771)	(3,897)
Other comprehensive income (loss) before reclassification adjustments	85	564
Amounts reclassified from AOCI	2	3
Tax benefit (provision)	1	17
Total other comprehensive income	88	585
Ending Balance	$ (3,682)	$ (3,313)