COMMON SHARES - Acquisition of TC Pipelines, LP (Details)	Mar. 03, 2021 shares
TC PipeLines, LP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares issued (in shares)	37,955,093

Number of shares of equity interests issued or issuable to acquire entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI https://asc.fasb.org/extlink&oid=126975305&loc=d3e6927-128479

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Balance Type:	na
Period Type:	duration