Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of voting equity interests acquired at the acquisition date in the business combination.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=126966197&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126975305&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126966197&loc=d3e6578-128477

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of tangible or intangible assets, including a business or subsidiary of the acquirer transferred by the entity to the former owners of the acquiree. Excludes cash.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI https://asc.fasb.org/extlink&oid=126975305&loc=d3e6927-128479

Name:	us-gaap_BusinessCombinationConsiderationTransferredOther1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of gain (loss) on sale or disposal of an equity method investment.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(b)(7)(c))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(b)(9)(a))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Name:	us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount, after tax, of reclassification adjustment from accumulated other comprehensive income (loss) for unrealized gain (loss) of investment classified as available-for-sale transferred to equity method.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17A
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL34724391-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 35
-Paragraph 33
-URI https://asc.fasb.org/extlink&oid=126903467&loc=d3e32804-111569

Name:	us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForInvestmentTransferredFromAvailableForSaleToEquityMethodAfterTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=126975305&loc=d3e6927-128479

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Business Acquisition, Value of Common Stock Shares Acquired

No definition available.

Name:	wba_BusinessAcquisitionValueOfCommonStockSharesAcquired
Namespace Prefix:	wba_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Business Combination, Cash Transferred for Preferred Units

No definition available.

Name:	wba_BusinessCombinationCashTransferredForPreferredUnits
Namespace Prefix:	wba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Business Combination, Consideration Transferred, Gross

No definition available.

Name:	wba_BusinessCombinationConsiderationTransferredGross
Namespace Prefix:	wba_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Business Combination, Consideration Transferred to Existing Stockholders

No definition available.