Other Non-Current Assets - Equity Method Investments (Details) $ in Millions	3 Months Ended
Mar. 31, 2021 USD ($) mi	Dec. 31, 2020 USD ($)
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 87	$ 81
Midship Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Length of Natural Gas Pipeline \| mi	200
Equity method investments	$ 87	$ 80

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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