Supplementary Financial Information Supplementary Financial Information (Other Income and Deductions) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Income and Expenses [Abstract]
Consent fee related to novation of hedge positions between counterparties	$ 0	$ 0	$ 0	$ 6
Insurance/litigation settlements	0	0	2	2
All other	1	2	5	4
Total other income	1	2	7	12
Impairment of mineral interests	0	24	0	24
Other Nonoperating Income, Other Asset Impairment Charges	3	0	3	0
Counterparty contract settlement	0	4	0	4
Other	5	2	9	9
Total other deductions	$ 8	$ 30	$ 12	$ 37

Consent Fee Related To Novation of Hedge Positions Between Counterparties, Nonoperating

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- Definition

The amount of expense related to the settlement of a contract with a counterparty.

+ References

No definition available.

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- Definition

Other nonoperating expenses not separately presented elsewhere.

+ References

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Other nonoperating income not separately presented elsewhere.

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- Definition

Other Nonoperating Income, Other Asset Impairment Charges

+ References

No definition available.

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- Definition

Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16373-109275

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The aggregate amount of other expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating expense recognized during the period. Such amounts may include: (a) unusual costs, (b) loss on foreign exchange transactions, (c) losses on securities (net of profits), and (d) miscellaneous other expense items.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 9

-Article 5

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-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.9)

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The aggregate amount of other income amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7)

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-Name Regulation S-X (SX)

-Number 210

-Section 03

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