Borrowings - long-term debt (Details)	Aug. 31, 2017 USD ($)	Aug. 31, 2017 GBP (£)	Aug. 31, 2017 EUR (€)	Aug. 28, 2017	Aug. 31, 2016 USD ($)
Long-Term Debt [Abstract]
Other	$ 24,000,000				$ 32,000,000
Total long-term debt, less current portion	$ 12,684,000,000				18,705,000,000
1.750% unsecured notes due 2018
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	1.75%	1.75%	1.75%
2.600% unsecured notes due 2021
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	2.60%	2.60%	2.60%
3.100% unsecured notes due 2023
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	3.10%	3.10%	3.10%
3.450% unsecured notes due 2026
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	3.45%	3.45%	3.45%
4.650% unsecured notes due 2046
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	4.65%	4.65%	4.65%
1.750% unsecured notes due 2017
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	1.75%	1.75%	1.75%
2.700% unsecured notes due 2019
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	2.70%	2.70%	2.70%
3.300% unsecured notes due 2021
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	3.30%	3.30%	3.30%
3.800% unsecured notes due 2024
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	3.80%	3.80%	3.80%
4.500% unsecured notes due 2034
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	4.50%	4.50%	4.50%
4.800% unsecured notes due 2044
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	4.80%	4.80%	4.80%
2.875% unsecured pound sterling notes due 2020
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	2.875%	2.875%	2.875%
3.600% unsecured pound sterling notes due 2025
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	3.60%	3.60%	3.60%
2.125% unsecured Euro notes due 2026
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	2.125%	2.125%	2.125%
3.100% unsecured notes due 2022
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	3.10%	3.10%	3.10%
4.400% unsecured notes due 2042
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	4.40%	4.40%	4.40%
5.250% unsecured notes due 2019
Long-Term Debt [Abstract]
Stated interest rate (as a percent)	5.25%	5.25%	5.25%
Total $6.0 billion debt issuance
Long-Term Debt [Abstract]
Face amount	$ 6,000,000,000
Fair value of the notes	2,500,000,000
Total $8.0 billion debt Issuance
Long-Term Debt [Abstract]
Face amount	8,000,000,000
Fair value of the notes	6,800,000,000
Total 700 million pounds debt issuance
Long-Term Debt [Abstract]
Face amount | £		£ 700,000,000.0
Fair value of the notes	1,000,000,000
Total 750 million euros debt issuance
Long-Term Debt [Abstract]
Face amount | €			€ 750,000,000.00
Fair value of the notes	900,000,000
Total $4.0 billion debt issuance
Long-Term Debt [Abstract]
Face amount	4,000,000,000
Fair value of the notes	1,700,000,000
Total $1.0 billion debt issuance
Long-Term Debt [Abstract]
Face amount	1,000,000,000
Fair value of the notes	300,000,000
Unsecured Debt | Unsecured pound sterling variable rate term loan due 2019
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	0				1,833,000,000
Unsecured Debt | 1.750% unsecured notes due 2018
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	0				1,246,000,000
Unsecured Debt | 2.600% unsecured notes due 2021
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	0				1,493,000,000
Unsecured Debt | 3.100% unsecured notes due 2023
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	0				744,000,000
Unsecured Debt | 3.450% unsecured notes due 2026
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	1,887,000,000				1,885,000,000
Unsecured Debt | 4.650% unsecured notes due 2046
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	590,000,000				590,000,000
Unsecured Debt | 1.750% unsecured notes due 2017
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	0				746,000,000
Stated interest rate (as a percent)				1.75%
Unsecured Debt | 2.700% unsecured notes due 2019
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	1,246,000,000				1,244,000,000
Unsecured Debt | 3.300% unsecured notes due 2021
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	1,244,000,000				1,242,000,000
Unsecured Debt | 3.800% unsecured notes due 2024
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	1,988,000,000				1,987,000,000
Unsecured Debt | 4.500% unsecured notes due 2034
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	495,000,000				494,000,000
Unsecured Debt | 4.800% unsecured notes due 2044
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	1,492,000,000				1,492,000,000
Unsecured Debt | 2.875% unsecured pound sterling notes due 2020
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	513,000,000				521,000,000
Unsecured Debt | 3.600% unsecured pound sterling notes due 2025
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	384,000,000				391,000,000
Unsecured Debt | 2.125% unsecured Euro notes due 2026
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	884,000,000				830,000,000
Unsecured Debt | 3.100% unsecured notes due 2022
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	1,195,000,000				1,194,000,000
Unsecured Debt | 4.400% unsecured notes due 2042
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	492,000,000				492,000,000
Unsecured Debt | 5.250% unsecured notes due 2019
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	$ 250,000,000				$ 249,000,000