Acquisitions, The preliminary identified definite and indefinite lived intangible assets (Details) (Alliance Boots [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Feb. 28, 2015
Definite-Lived Intangible Assets [Roll Forward]
Amount	$ 2,998
Indefinite-Lived Intangible Assets [Roll Forward]
Amount	8,463
Trade Names and Trademarks [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Amount	6,192
Pharmacy Licenses [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Amount	2,271
Customer Relationships [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life (in years)	12 years
Amount	1,676
Loyalty Card Holders [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life (in years)	12 years
Amount	723
Trade Names and Trademarks [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life (in years)	15 years
Amount	544
Favorable Lease Interests [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life (in years)	3 years
Amount	$ 55