Acquisitions, The Preliminary Identified Definite and Indefinite Lived Intangible Assets (Details) $ in Millions		12 Months Ended
	Dec. 31, 2014 USD ($) Segment	Aug. 31, 2016 USD ($) Segment	Aug. 31, 2015 USD ($)	Aug. 31, 2014 USD ($)
Indefinite-Lived Intangible Assets [Roll Forward]
Goodwill		$ 23	$ 14,972
Number of reportable segments | Segment	3	3
Selling, general and administrative expenses		$ 23,910	22,400	$ 17,992
Fair value of the assets acquired		3,700
Estimated manufacturing profit in acquired finished goods inventory capitalized		106
Retail Pharmacy International [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Goodwill		23	4,036
Retail Pharmacy USA [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Goodwill		0	7,290
Goodwill arising from synergies		3,500
Goodwill based on a with and without analysis		3,800
Pharmaceutical Wholesale [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Goodwill		$ 0	3,646
Alliance Boots [Member]
Definite-Lived Intangible Assets [Roll Forward]
Amount	$ 2,545
Indefinite-Lived Intangible Assets [Roll Forward]
Amount	9,146
Selling, general and administrative expenses			$ 87
Trade Names and Trademarks [Member] | Alliance Boots [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Amount	6,657
Pharmacy Licenses [Member] | Alliance Boots [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Amount	$ 2,489
Customer Relationships [Member] | Alliance Boots [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life	12 years
Amount	$ 1,311
Loyalty Card Holders [Member] | Alliance Boots [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life	20 years
Amount	$ 742
Trade Names and Trademarks [Member] | Alliance Boots [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life	9 years
Amount	$ 399
Favorable Lease Interests [Member] | Alliance Boots [Member]
Definite-Lived Intangible Assets [Roll Forward]
Weighted-Average Useful Life	7 years
Amount	$ 93