Summary of Major Accounting Policies (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Cash and Cash Equivalents [Abstract]
Minimum number of days for settlement of credit and debit charges	2 days
Maximum number of days for settlement of credit and debit charges	7 days
Credit and debit card receivables	$ 114	$ 165
Restricted Cash [Abstract]
Restricted cash	185	184
Accounts Receivable [Abstract]
Allowance for doubtful accounts	166	172	$ 173
Inventory [Line Items]
Inventory, LIFO Reserve	2,800	2,500
Total carrying value of inventory	8,956	8,678
Property, Plant and Equipment [Line Items]
Property and equipment	22,935	22,608
Less: accumulated depreciation and amortization	8,600	7,540
Property and equipment, net	14,335	15,068
Depreciation expense for property and equipment	1,300	1,300	923
Impaired Assets [Abstract]
Impairment charges	30	110
Liabilities for Store Closings [Abstract]
Reserve for store closings	466	446
Advertising Costs [Abstract]
Net advertising expenses included in selling, general and administrative expenses	$ 598	$ 491	$ 265
Earnings Per Share [Abstract]
Outstanding options to purchase common shares excluded from earnings per share calculations (in shares)	2.5	2.5	3.5
Minimum [Member]
Derivative [Line Items]
Highly effective hedging percentage	80.00%
Maximum [Member]
Derivative [Line Items]
Highly effective hedging percentage	125.00%
Selling, General and Administrative Expenses [Member]
Impaired Assets [Abstract]
Impairment charges			$ 167
Retail Pharmacy USA [Member]
Inventory [Line Items]
Total carrying value of inventory	$ 6,100	$ 5,600
Retail Pharmacy International and Pharmaceutical Wholesale [Member]
Inventory [Line Items]
Total carrying value of inventory	2,900	3,100
Cost Transformation Restructuring Program [Member]
Liabilities for Store Closings [Abstract]
Reserve for store closings	91
Cost Transformation Restructuring Program [Member] | Selling, General and Administrative Expenses [Member]
Impaired Assets [Abstract]
Impairment charges	$ 305	386
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	20 years
Property and equipment	$ 3,738	3,687
Buildings and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 7,557	7,705
Buildings and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	3 years
Buildings and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	50 years
Fixtures and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 9,064	8,904
Fixtures and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	3 years
Fixtures and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life of assets	20 years
Capitalized System Development Costs and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 1,787	1,491
Internally developed software amortization	238	178	$ 127
Unamortized capitalized software costs	$ 900	1,000
Capitalized System Development Costs and Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life of capitalized software costs	3 years
Capitalized System Development Costs and Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life of capitalized software costs	8 years
Capital Lease Properties [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 789	$ 821