Concentration Risk and Guarantor Obligations [Line Items]

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- Definition

Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure for Single Counter Party

+ References

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- Definition

Concentration Risk, Number of Customers Provided Service

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- Definition

Long-term Contract for Purchase of Electric Power, Term of Contract

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- Definition

Number Of Counterparties

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- Definition

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624258-113959

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624258-113959

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- Definition

Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

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-Section 50

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-Section 50

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- Definition

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (c)

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Credit Risk (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended
Credit Risk (Narrative) (Details) $ in Millions	Sep. 30, 2015 USD ($) customer Counterparty	Sep. 30, 2015 USD ($) Counterparty	Dec. 31, 2014 USD ($)
Concentration Risk and Guarantor Obligations [Line Items]
Gross credit exposure		$ 195
Number of counterparties \| Counterparty	0	0
Additional collateral to be posted if the credit related contingent features were triggered	$ 14	$ 14	$ 20
Collateral posted			1
Aggregate fair value of all derivative instruments with credit contingent provisions that are in a liability position	$ 32	$ 32	$ 49
Investment Grade \| Investment grade counterparties
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)		64.00%
Investment Grade \| Counterparty, A
Concentration Risk and Guarantor Obligations [Line Items]
Amount of exposure for single counterparty		$ 35
DTI \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	95.00%
Number of customers \| customer	244
DTI \| Ten Largest Customers \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	45.00%
Number of customers \| customer	10
DTI \| Thirty Largest Customers \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	72.00%
Number of customers \| customer	30
DTI \| Long Term Transmission Capacity Contracts [Member] \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	98.00%
Term of contract	2 years
DTI \| Annual Capacity Contracts \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	2.00%
DTI \| Unsubscribed Firm Transportation Capacity \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	1.00%
DTI \| Long Term Storage Capacity Contracts \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	99.00%
DTI \| Unsubscribed Storage Capacity \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	1.00%
East Ohio \| Customer Concentration Risk \| Storage and Transportation Revenue
Concentration Risk and Guarantor Obligations [Line Items]
Concentration risk, percentage (percentage)	99.00%