Debt - short and long-term debt (Details)	12 Months Ended
	Aug. 31, 2023 USD ($)	Aug. 31, 2022 USD ($)	Aug. 31, 2021 USD ($)	Aug. 31, 2023 GBP (£)	Aug. 31, 2023 EUR (€)	Dec. 19, 2022 USD ($)	Nov. 17, 2021 USD ($)	Nov. 15, 2021 USD ($)
Debt Instrument [Line Items]
Total short-term debt	$ 917,000,000	$ 1,059,000,000
Other	20,000,000	26,000,000
Total long-term debt, less current portion	8,145,000,000	10,615,000,000
Long-term debt purchased and retired	8,978,000,000	8,360,000,000	$ 15,257,000,000
Loss on early extinguishment of debt	0	6,000,000	414,000,000
0.9500% notes payable, due 2023
Debt Instrument [Line Items]
Total short-term debt	850,000,000	0
Other
Debt Instrument [Line Items]
Total short-term debt	68,000,000	59,000,000
Unsecured credit facility, 3 year term, due 2026 | Credit facilities
Debt Instrument [Line Items]
Face amount						$ 1,000,000,000
Unsecured notes
Debt Instrument [Line Items]
Loss on early extinguishment of debt		6,000,000	$ 387,000,000
Unsecured notes | 0.9500% notes payable, due 2023
Debt Instrument [Line Items]
Face amount	$ 850,000,000						$ 850,000,000
Stated interest rate (as a percent)	0.95%			0.95%	0.95%		95.00%
Long-term debt	$ 0	848,000,000
Unsecured notes | $1.5 billion debt issuance
Debt Instrument [Line Items]
Face amount	$ 1,500,000,000
Unsecured notes | 3.200% unsecured notes due 2030
Debt Instrument [Line Items]
Stated interest rate (as a percent)	3.20%			3.20%	3.20%
Long-term debt	$ 498,000,000	498,000,000
Unsecured notes | 4.100% unsecured notes due 2050
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.10%			4.10%	4.10%
Long-term debt	$ 793,000,000	792,000,000
Unsecured notes | Total $6 billion note issuance
Debt Instrument [Line Items]
Face amount	$ 6,000,000,000
Unsecured notes | 3.450% unsecured notes due 2026
Debt Instrument [Line Items]
Stated interest rate (as a percent)	3.45%			3.45%	3.45%
Long-term debt	$ 1,444,000,000	1,443,000,000
Unsecured notes | 4.650% unsecured notes due 2046
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.65%			4.65%	4.65%
Long-term debt	$ 318,000,000	318,000,000
Unsecured notes | Total $8 billion note issuance
Debt Instrument [Line Items]
Face amount	$ 8,000,000,000
Unsecured notes | 3.800% unsecured notes due 2024
Debt Instrument [Line Items]
Stated interest rate (as a percent)	3.80%			3.80%	3.80%
Long-term debt	$ 1,156,000,000	1,155,000,000
Unsecured notes | 4.500% unsecured notes due 2034
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.50%			4.50%	4.50%
Long-term debt	$ 301,000,000	301,000,000
Unsecured notes | 4.800% unsecured notes due 2044
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.80%			4.80%	4.80%
Long-term debt	$ 869,000,000	869,000,000
Unsecured notes | Total £700 million note issuance
Debt Instrument [Line Items]
Face amount | £				£ 700,000,000
Unsecured notes | 3.600% unsecured Pound sterling notes due 2025
Debt Instrument [Line Items]
Stated interest rate (as a percent)	3.60%			3.60%	3.60%
Long-term debt	$ 381,000,000	354,000,000
Unsecured notes | Total €750 million note issuance
Debt Instrument [Line Items]
Face amount | €					€ 750,000,000
Unsecured notes | 2.125% unsecured Euro notes due 2026
Debt Instrument [Line Items]
Stated interest rate (as a percent)	2.125%			2.125%	2.125%
Long-term debt	$ 814,000,000	752,000,000
Unsecured notes | Total $4 billion note issuance
Debt Instrument [Line Items]
Face amount	$ 4,000,000,000
Unsecured notes | 4.400% unsecured notes due 2042
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.40%			4.40%	4.40%
Long-term debt	$ 263,000,000	263,000,000
Term loan | Credit facilities
Debt Instrument [Line Items]
Face amount								$ 3,000,000,000
Credit facilities | November 2021 DDTL due November 2023
Debt Instrument [Line Items]
Long-term debt	0	1,998,000,000
Credit facilities | November 2021 DDTL due November 2024
Debt Instrument [Line Items]
Long-term debt	289,000,000	999,000,000
Credit facilities | December 2022 DDTL due January 2026
Debt Instrument [Line Items]
Long-term debt	999,000,000	0
Credit facilities | November 2021 DDTL due February 2023
Debt Instrument [Line Items]
Total short-term debt	0	$ 1,000,000,000
Unsecured notes | 0.9500% notes payable, due 2023
Debt Instrument [Line Items]
Face amount	$ 850,000,000
Stated interest rate (as a percent)	0.95%			0.95%	0.95%