Derivative Instruments Table - I/S Impact (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in value recognized in AOCI on derivatives (effective portion)	$ 0	$ 0	$ (4)
Derivatives Not Designated In A Hedging Relationships
Amount of gain/(loss) recognized in income on derivatives	96	(3)	30
Revenue [Member] \| Derivatives In Cash Flow Hedging Relationship \| Commodity Derivatives
Amount of gain/(loss) reclassified from AOCI into income (effective portion)	0	0	6
Revenue [Member] \| Derivatives Not Designated In A Hedging Relationships \| Commodity Derivatives
Amount of gain/(loss) from de-designation amortized from AOCI into income	0	0	-5
Amount of gain/(loss) recognized in income on derivatives	93	(9)	16
Other Income and Deductions [Member] \| Derivatives Not Designated In A Hedging Relationships \| Embedded Derivatives
Amount of gain/(loss) recognized in income on derivatives	$ 3	$ 6	$ 14

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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