Derivative Financial Instruments (Schedule Of Derivative Financial Instruments Included In The Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Derivatives Fair Value [Line Items]
Fair value of derivative assets	$ 11	$ 45
Fair value of derivative liabilities	244	48
Other Current Liabilities [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative liabilities	187	22
Commodity Derivatives [Member] \| Other Current Assets [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative assets	9	34
Commodity Derivatives [Member] \| Other Long-Term Assets [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative assets	1	1
Commodity Derivatives [Member] \| Other Current Liabilities [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative liabilities	187	14
Commodity Derivatives [Member] \| Other Long-Term Liabilities [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative liabilities	16	4
Interest Rate Derivatives [Member] \| Other Current Assets [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative assets	1	1
Interest Rate Derivatives [Member] \| Other Long-Term Assets [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative assets		1
Interest Rate Derivatives [Member] \| Other Long-Term Liabilities [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative liabilities	$ 41	22
Foreign Currency Derivatives [Member] \| Other Current Assets [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative assets		8
Foreign Currency Derivatives [Member] \| Other Current Liabilities [Member]
Derivatives Fair Value [Line Items]
Fair value of derivative liabilities		$ 8

Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as an asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624163-113959

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- Definition

Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as a liability.

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