Goodwill and Other Intangible Assets, Schedule of Finite-Lived Intangible Assets by Major Class (Details) (USD $) In Millions, unless otherwise specified	Feb. 28, 2015	Aug. 31, 2014	Feb. 28, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	$ 4,780	$ 2,108
Accumulated amortization	942	936
Total amortizable intangible assets, net	3,838	1,172
Total indefinite lived intangible assets	8,387	8
Total intangible assets, net	12,225	1,180
Purchased Prescription File [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	925	1,079
Accumulated amortization	471	474
Favorable lease interests [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	427	382
Accumulated amortization	187	174
Purchasing and Payer Contract [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	95	301
Accumulated amortization	61	145
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	154	151
Accumulated amortization	82	70
Trade names and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	735	191
Accumulated amortization	84	69
Total indefinite lived intangible assets	6,136	8
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	1,724	0
Accumulated amortization	46	0
Loyalty Card Holders [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	716	0
Accumulated amortization	10	0
Other Amortizable Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amortizable Intangible Assets	4	4
Accumulated amortization	1	4
Pharmacy Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Total indefinite lived intangible assets	$ 2,251	$ 0