Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

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Asset Purchase Agreement Consideration to be Transferred

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Asset Purchase Agreement, Number of Distribution Centers Expected To Be Acquired

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Asset Purchase Agreement, Number of Stores Expected To Be Acquired

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Number of Locations Acquired

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Acquisitions - narrative (Details) $ in Millions			12 Months Ended
Acquisitions - narrative (Details) $ in Millions	Sep. 19, 2017 USD ($) distribution_center store	Mar. 31, 2017 USD ($)	Aug. 31, 2018 USD ($) distribution_center store	Aug. 31, 2017 USD ($)	Aug. 31, 2016 USD ($)
Business Acquisition [Line Items]
Goodwill			$ 16,914	$ 15,632	$ 15,527
Rite Aid
Business Acquisition [Line Items]
Number of stores expected to be acquired \| store	1,932
Number of distribution centers expected to be acquired \| distribution_center	3		2
Consideration to be transferred	$ 4,375
Number of stores acquired \| store			1,932
Consideration	4,330		$ 4,157
Goodwill	$ 1,344
AllianceRx Walgreens Prime
Business Acquisition [Line Items]
Goodwill		$ 103
Total consideration		$ 720
Customer Contracts \| AllianceRx Walgreens Prime
Business Acquisition [Line Items]
Weighted average useful life		15 years