Document and Entity Information	9 Months Ended
	May 31, 2019 shares
Document and Entity Information [Abstract]
Entity Registrant Name	Walgreens Boots Alliance, Inc.
Entity Central Index Key	0001618921
Current Fiscal Year End Date	--08-31
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)	903,143,463
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	May 31, 2019