Commitments and Contingencies - Legal Matters (Details) - USA Power [Member] $ in Millions	9 Months Ended
Sep. 30, 2015 USD ($)
Loss Contingencies [Line Items]
Loss Contingency, Original Damages Sought, Legal Fees as a Percentage of Damages	40.00%
Loss Contingency, Damages Awarded, Value	$ 113
Loss Contingency, Damages and Attorney Fees Awarded, Value	115
Loss Contingency Accrual, at Carrying Value	121
Amount Awarded for Actual Damages [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded by Jury, Value	18
Amount Awarded for Unjust Enrichment [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Awarded by Jury, Value	$ 113

Amount of damages the jury awarded to the plaintiff for breach of contract and misappropriation of a trade secret.

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- Definition

Amount of damages and attorney's fees awarded to the plaintiff in the legal matter.

+ References

No definition available.

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- Definition

Percentage of the total amount to be awarded in the case that the plaintiff originally sought for legal fees.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of loss contingency liability.

+ References

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- Definition

Amount of damages awarded to the plaintiff in the legal matter.

+ 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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-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

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-Paragraph 4

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

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-Section 50

-Paragraph 9

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-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

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