Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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

Summary of major accounting policies - impaired assets (Details) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Restructuring Cost and Reserve [Line Items]
Impairment charges	$ (11)	$ 30	$ 110
Selling, general and administrative expense
Restructuring Cost and Reserve [Line Items]
Impairment charges		$ 305	$ 386
Cost Transformation Program \| Selling, general and administrative expense
Restructuring Cost and Reserve [Line Items]
Impairment charges	$ 234