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

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-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

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
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- Definition

Monetary value of the issuance of new units of limited partnership interest in a public offering, net of offering costs. This is a parenthetical disclosure.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
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-Paragraph 1
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Period Type:	duration

- Definition

The number of units sold in a public offering of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
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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

No definition available.

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PARTNERS' EQUITY - ATM Equity Issuance Program (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
ATM Equity Issuance Program \| Common units
PARTNERS' EQUITY
Common units issued (in units)		0	700,000
Net proceeds from issuance of common units			$ 39
ATM Equity Issuance Program \| TC Pipelines, LP \| General Partner
PARTNERS' EQUITY
Equity contribution			$ 1
TC Pipelines, LP
PARTNERS' EQUITY
Ownership interest in the partnership	2.00%
TC Pipelines, LP \| General Partner \| Common units
PARTNERS' EQUITY
Ownership interest in the partnership	2.00%	2.00%	2.00%