FINANCIAL CHARGES AND OTHER (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
FINANCIAL CHARGES AND OTHER
Interest Expense	$ 23	$ 23	$ 71	$ 59
PNGTS' amortization of loss on derivative instruments (Note 13)			2	1
Net realized (gain) loss related to the interest rate swaps			(2)
Other income			(2)	(1)
Financial charges and other	$ 23	$ 23	$ 69	$ 59

Amount of cash outflow in the form amortization of derivatives loss.

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- Definition

The aggregate of interest and debt related expenses associated with nonoperating financing activities of the entity and the net amount of other income and expense amounts, the components of which are not separately disclosed on the income statement.

+ References

No definition available.

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

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- Definition

The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section 50
-Paragraph 4C
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-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

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- References

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Amount of income related to nonoperating activities, classified as other.

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-Name Accounting Standards Codification
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