Trade Accounts Receivable Sale Programs (Trade Accounts Receivable Sale Programs Amounts Recognized) (Details) - Trade Accounts Receivable Sale Programs - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Feb. 29, 2020	Feb. 28, 2019	Feb. 29, 2020	Feb. 28, 2019
Trade Accounts Receivable Securitization and Sale Program [Line Items]
Trade accounts receivable sold	$ 2,201	$ 1,719	$ 4,163	$ 3,553
Cash proceeds received	2,196	1,712	4,153	3,538
Pre-tax losses on sale of receivables	$ 5	$ 7	$ 10	$ 15

Cash Flows between a transferor and a transferee attributable to collections reinvested in revolving period transfers related to either a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=118948506&loc=d3e107207-111719

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