Common Units Issued During Period, Subject to Rescission, Expiration Period From The Date Of Purchase

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- Definition

Common Units Issued During Period, Subject to Rescission, Shares

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No definition available.

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- Definition

Common Units Outstanding, Subject to Rescission Or Redemption, Amount

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- Definition

Noncontrolling Interest, Decrease from Redemptions Or Purchase Of Interests, Price Per Share

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No definition available.

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- Definition

Noncontrolling Interest, Stub Period Distribution Payments Acquired Per Unit

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No definition available.

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- Definition

Partially Owned Subsidiary, Percentage of Ownership Interest Sold

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No definition available.

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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- Definition

Decrease in noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569655-111683

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-Publisher FASB
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4616395-111683

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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.

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No definition available.

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

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NON-CONTROLLING INTERESTS - Narrative (Details) $ / shares in Units, shares in Millions, CAD in Millions, $ in Millions				2 Months Ended	5 Months Ended	12 Months Ended
	Jun. 01, 2017	Feb. 17, 2017 USD ($) $ / shares	Jan. 01, 2016	May 19, 2016 shares	May 31, 2017 CAD	Dec. 31, 2017 CAD	Dec. 31, 2016 CAD	Dec. 31, 2015 CAD	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Jul. 01, 2016
Non-controlling interests
Asset impairment charges						CAD 1,257	CAD 1,388	CAD 3,745
Common units outstanding, subject to rescission, amount						0	1,179
Noncontrolling Interest
Non-controlling interests
Share price (in dollars per share) \| $ / shares		$ 17.00
Stub period distribution payments acquired (in dollars per share) \| $ / shares		$ 0.10
Aggregate transaction value		$ 921				41	40	11
Columbian Pipeline \| Noncontrolling Interest
Non-controlling interests
Percentage of non-controlling interests											53.50%
Columbia Pipeline Partners LP
Non-controlling interests
Common units outstanding, subject to rescission, amount							1,073			$ 799
TC PipeLines, LP
Non-controlling interests
Asset impairment charges \| $									$ 199
Fees received for services provided						CAD 5	5	CAD 4
Common units outstanding, subject to rescission, amount							CAD 106			$ 82
Reclassification to Common Units of CPPL, subject to redemption (in shares) \| shares				1.6
Expiration period from the date of purchase				1 year
TC PipeLines, LP \| Noncontrolling Interest
Non-controlling interests
Percentage of non-controlling interests						74.30%	73.20%			73.20%
Asset impairment charges \| $									$ 143
TC PipeLines, LP \| Noncontrolling Interest \| Minimum
Non-controlling interests
Percentage of non-controlling interests							72.00%	71.70%	71.70%	72.00%
TC PipeLines, LP \| Noncontrolling Interest \| Maximum
Non-controlling interests
Percentage of non-controlling interests							73.20%	72.00%	72.00%	73.20%
Portland Natural Gas Transmission System
Non-controlling interests
Fees received for services provided					CAD 4		CAD 10	CAD 11
Portland Natural Gas Transmission System \| Noncontrolling Interest
Non-controlling interests
Percentage of non-controlling interests						0.00%	38.30%			38.30%
Ownership interest before transaction, percent	11.81%		49.90%