Divestitures and Other Transactions Divestitures and Other Transactions - Divested Ag Business Depreciation and Capital Expenditures (Details) - Divested Ag Business [Member] - USD ($) $ in Millions	4 Months Ended	8 Months Ended
Dec. 31, 2017	Aug. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation	$ 0	$ 21
Capital Expenditures	$ 5	$ 8

Amount of capital expenditure attributable to discontinued operations.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760

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