Goodwill and Other Intangible Assets, Schedule of Finite-Lived Intangible Assets by Major Class (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2015	Aug. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 4,387	$ 2,108
Accumulated amortization	1,090	936
Total amortizable intangible assets, net	3,297	1,172
Total indefinite lived intangible assets	9,054	8
Total intangible assets, net	12,351	1,180
Purchased Prescription Files [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	885	1,079
Accumulated amortization	$ 470	$ 474
Weighted-average amortization period	6 years	6 years
Favorable Lease Interests [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 440	$ 382
Accumulated amortization	$ 207	$ 174
Weighted-average amortization period	13 years	11 years
Purchasing and Payer Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 94	$ 301
Accumulated amortization	$ 65	$ 145
Weighted-average amortization period	10 years	13 years
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 154	$ 151
Accumulated amortization	$ 92	$ 70
Weighted-average amortization period	5 years	5 years
Trade Names and Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 675	$ 191
Accumulated amortization	83	69
Total indefinite lived intangible assets	$ 6,590	$ 8
Weighted-average amortization period	9 years	12 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 1,409	$ 0
Accumulated amortization	$ 132	$ 0
Weighted-average amortization period	12 years	0 years
Loyalty Card Holders [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 730	$ 0
Accumulated amortization	$ 41	$ 0
Weighted-average amortization period	12 years	0 years
Other Amortizable Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 0	$ 4
Accumulated amortization	$ 0	$ 4
Weighted-average amortization period	0 years	8 years
Pharmacy Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Total indefinite lived intangible assets	$ 2,464	$ 0