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.

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Total contributions made by each class of partners (i.e., general, limited and preferred partners).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

+ Details

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Balance Type:	credit
Period Type:	duration

- Details

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- Details

Name:	dei_LegalEntityAxis=us-gaap_ParentCompanyMember
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- Details

Name:	dei_LegalEntityAxis=tclp_TCPipeLinesGeneralPartnershipIncorporatedMember
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GTN ACQUISITION (Details 3) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
GTN ACQUISITION (Details 3) - USD ($) $ in Millions	Apr. 02, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
GTN ACQUISITION
Equity contribution				$ 2
General Partner
GTN ACQUISITION
Equity contribution				$ 2
General Partner \| Partnership
GTN ACQUISITION
Equity contribution	$ 2
General Partner \| TC PipeLines GP, Inc.
GTN ACQUISITION
Ownership interest in the Partnership (as a percent)	2.00%	2.00%	2.00%	2.00%	2.00%