Accounting policies (Policies)	3 Months Ended
Nov. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of presentation The Consolidated Condensed Financial Statements of Walgreens Boots Alliance, Inc. (“Walgreens Boots Alliance” or the “Company”) included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission regarding interim financial reporting. The Consolidated Condensed Financial Statements include all subsidiaries in which the Company holds a controlling interest. Investments in less than majority-owned subsidiaries in which the Company does not have a controlling interest, but does have significant influence, are accounted for as equity method investments. All intercompany transactions have been eliminated. The Consolidated Condensed Balance Sheets as of November 30, 2017 and August 31, 2017, the Consolidated Condensed Statements of Equity, the Consolidated Condensed Statements of Earnings, the Consolidated Condensed Statements of Comprehensive Income, and the Consolidated Condensed Statements of Cash Flows for the three months ended November 30, 2017 and 2016 are unaudited. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) have been condensed or omitted pursuant to such rules and regulations, although the Company believes that the disclosures are adequate to make the information presented not misleading. These unaudited Consolidated Condensed Financial Statements should be read in conjunction with the audited financial statements and the notes thereto included in the Walgreens Boots Alliance Annual Report on Form 10-K for the fiscal year ended August 31, 2017. The Company has evaluated subsequent events from the balance sheet date through the date the financial statements were issued and determined there were no subsequent events to disclose other than as disclosed in notes 5 and 19. In the opinion of the Company, the unaudited Consolidated Condensed Financial Statements for the interim periods presented include all adjustments (consisting only of normal recurring adjustments) necessary to present a fair statement of the results for such interim periods. The influence of certain holidays, seasonality, foreign currency rates, changes in vendor, payer and customer relationships and terms and other factors on the Company’s operations, net earnings for any period may not be comparable to the same period in previous years. With respect to the Company’s Retail Pharmacy USA segment, the positive impact on gross profit margins and gross profit dollars typically has been significant in the first several months after a generic version of a drug is first allowed to compete with the branded version, which is generally referred to as a “generic conversion”. In any given year, the number of major brand name drugs that undergo a conversion from branded to generic status can increase or decrease, which can have a significant impact on the Company’s Retail Pharmacy USA segment’s sales, gross profit margins and gross profit dollars making the Company’s operations or net earnings for any period incomparable.

Basis of presentation

The Consolidated Condensed Financial Statements of Walgreens Boots Alliance, Inc. (“Walgreens Boots Alliance” or the “Company”) included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission regarding interim financial reporting. The Consolidated Condensed Financial Statements include all subsidiaries in which the Company holds a controlling interest. Investments in less than majority-owned subsidiaries in which the Company does not have a controlling interest, but does have significant influence, are accounted for as equity method investments. All intercompany transactions have been eliminated.

The Consolidated Condensed Balance Sheets as of November 30, 2017 and August 31, 2017, the Consolidated Condensed Statements of Equity, the Consolidated Condensed Statements of Earnings, the Consolidated Condensed Statements of Comprehensive Income, and the Consolidated Condensed Statements of Cash Flows for the three months ended November 30, 2017 and 2016 are unaudited. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) have been condensed or omitted pursuant to such rules and regulations, although the Company believes that the disclosures are adequate to make the information presented not misleading. These unaudited Consolidated Condensed Financial Statements should be read in conjunction with the audited financial statements and the notes thereto included in the Walgreens Boots Alliance Annual Report on Form 10-K for the fiscal year ended August 31, 2017. The Company has evaluated subsequent events from the balance sheet date through the date the financial statements were issued and determined there were no subsequent events to disclose other than as disclosed in notes 5 and 19.

In the opinion of the Company, the unaudited Consolidated Condensed Financial Statements for the interim periods presented include all adjustments (consisting only of normal recurring adjustments) necessary to present a fair statement of the results for such interim periods. The influence of certain holidays, seasonality, foreign currency rates, changes in vendor, payer and customer relationships and terms and other factors on the Company’s operations, net earnings for any period may not be comparable to the same period in previous years. With respect to the Company’s Retail Pharmacy USA segment, the positive impact on gross profit margins and gross profit dollars typically has been significant in the first several months after a generic version of a drug is first allowed to compete with the branded version, which is generally referred to as a “generic conversion”. In any given year, the number of major brand name drugs that undergo a conversion from branded to generic status can increase or decrease, which can have a significant impact on the Company’s Retail Pharmacy USA segment’s sales, gross profit margins and gross profit dollars making the Company’s operations or net earnings for any period incomparable.