Goodwill and Other Intangible Assets, Schedule of Finite-Lived Intangible Assets by Major Class (Details) - USD ($) $ in Millions	May. 31, 2015	Aug. 31, 2014	May. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 4,167	$ 2,108
Accumulated amortization	971	936
Total amortizable intangible assets, net	3,196	1,172
Total indefinite lived intangible assets	8,033	8
Total intangible assets, net	11,229	1,180
Purchased Prescription Files [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	866	1,079
Accumulated amortization	436	474
Favorable Lease Interests [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	378	382
Accumulated amortization	198	174
Purchasing and Payer Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	94	301
Accumulated amortization	63	145
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	151	151
Accumulated amortization	83	70
Trade Names and Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	453	191
Accumulated amortization	63	69
Total indefinite lived intangible assets	5,509	8
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	1,435	0
Accumulated amortization	100	0
Loyalty Card Holders [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	735	0
Accumulated amortization	26	0
Other Amortizable Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	55	4
Accumulated amortization	2	4
Pharmacy Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Total indefinite lived intangible assets	$ 2,524	$ 0