Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2019	Nov. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 24,152	$ 26,689
Total other comprehensive income (loss)	600	(232)
Ending Balance	24,314	26,263
Pension/ post-retirement obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(48)	101
Other comprehensive income (loss) before reclassification adjustments	(12)	0
Amounts reclassified from AOCI	2	(4)
Tax benefit (provision)	2	0
Total other comprehensive income (loss)	(7)	(4)
Ending Balance	(55)	97
Unrealized gain (loss) on cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(24)	(30)
Other comprehensive income (loss) before reclassification adjustments	(1)	3
Amounts reclassified from AOCI	1	1
Tax benefit (provision)	0	(1)
Total other comprehensive income (loss)	0	3
Ending Balance	(24)	(27)
Net investment hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	55	0
Other comprehensive income (loss) before reclassification adjustments	(55)	0
Amounts reclassified from AOCI		0
Tax benefit (provision)	13	0
Total other comprehensive income (loss)	(42)	0
Ending Balance	14	0
Share of OCI of equity method investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	3	3
Other comprehensive income (loss) before reclassification adjustments	(10)	1
Amounts reclassified from AOCI	0	0
Tax benefit (provision)	2	0
Total other comprehensive income (loss)	(8)	1
Ending Balance	(5)	4
Cumulative translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,884)	(3,076)
Other comprehensive income (loss) before reclassification adjustments	642	(228)
Amounts reclassified from AOCI	0	0
Tax benefit (provision)	0	(1)
Total other comprehensive income (loss)	642	(229)
Ending Balance	(3,242)	(3,305)
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,897)	(3,002)
Other comprehensive income (loss) before reclassification adjustments	564	(224)
Amounts reclassified from AOCI	3	(3)
Tax benefit (provision)	17	(2)
Total other comprehensive income (loss)	585	(229)
Ending Balance	$ (3,313)	$ (3,231)