EQUITY METHOD INTERESTS - Additional Information (Details) - ALTM $ in Millions	Dec. 31, 2020 USD ($) entity	Dec. 31, 2019 USD ($) entity
Schedule of Equity Method Investments [Line Items]
Number of long-haul pipeline entities \| entity	4	4
Difference between carrying amount and underlying equity amount \| $	$ 38	$ 30

Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Name:	us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant