Stock Compensation Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
Nov. 30, 2014	Nov. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares authorized under Omnibus Plan (in shares)	60,400,000
Total stock based compensation expense for the period	$ 31us-gaap_ShareBasedCompensation	$ 21us-gaap_ShareBasedCompensation
Cliff vesting schedule	3 years
Performance period	3 years
Walgreen Co. Omnibus and former Executive Stock Option Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted in period (in shares)	4,102,510	6,385,078
Fully recognized retiree eligible expense	1	3
Grant date fair value (in dollars per share)	$ 14.64
Volatility rate (in hundredths)	25.51%
Dividend yield (in hundredths)	1.79%
Expected term	6 years 8 months 5 days
Walgreen Co. Omnibus and former Restricted Stock Unit Award Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted in period (in shares)	904,952	610,887
Number of other than options granted during the period (in shares)	20,554	21,298
Grant date fair value restricted and performance shares (in dollars per share)	$ 63.83
Walgreen Co. Omnibus and former Performance Share Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted in period (in shares)	480,323	697,132
Grant date fair value restricted and performance shares (in dollars per share)	$ 65.31
Total Omnibus plan and former Restricted Stock Unit Award Program and Walgreen Co. Performance Share Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock based compensation expense for the period	$ 19	$ 10

The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Weighted average expected volatility rate of share-based compensation awards.

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Net number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The amount of expense recognized during the period for options issued to all employees that are retiree eligible.

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Total number of shares available for delivery under the Walgreen Co. Omnibus Incentive Plan

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