Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 16,372	$ 2,359	$ 2,410
Goodwill impairment	706
Amortization expense for intangible assets	480	282	$ 289
Alliance Boots [Member]
Business Acquisition [Line Items]
Goodwill	14,849
Intangible assets	11,691
Purchase price	$ 15,851
Take Care Employer Solutions [Member]
Business Acquisition [Line Items]
Goodwill impairment		92
Kerr Drug [Member]
Business Acquisition [Line Items]
Goodwill		42
Intangible assets		54
Purchase price		$ 170